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1.05 Common Clinical Diagnoses and Conditions: Asthma
Introduction
Asthma is one of the most common, non-communicable, chronic childhood diseases. It is a leading cause of healthcare utilization resulting in a significant number of primary care visits, emergency room visits, and hospitalizations. It has direct impact on patient quality of life with a heavy financial burden to individuals and society. The prevalence of asthma continues to rise and is not equally distributed throughout the population, differing by sex, race, socioeconomic level, and geographic location. The Department of Health and Human Services (DHHS) recognizes the weight of asthma disease on our society, having directed the National Institute of Health to create evidence-based guidelines for asthma care. Additionally, the DHHS continues to recognize asthma as a key element of the Healthy People 2020 initiative with several specific health objectives related directly to inpatient management. Due to the chronic nature of this disease, pediatric hospitalists should not only treat acute exacerbations resulting in status asthmaticus, but also create or reaffirm long-term management plans.
Knowledge
Pediatric hospitalists should be able to:
- Discuss the pathophysiology of asthma addressing both bronchoconstrictive and inflammatory components, and state how each impact pharmacologic treatment choices.
- Compare and contrast the pathophysiology of asthma with other common small airway illnesses in children, such as bronchiolitis, viral pneumonia with bronchospasm, or chronic lung disease.
- Describe disparities in asthma prevalence by sex, race, socioeconomic level, and geographic location.
- Discuss the role psychosocial factors (such as housing, parental mental health, financial status, lack of health insurance, and others) play in the risk for exposure to allergens, non-compliance to medical regimens, and access to health care.
- List the differential diagnosis of wheezing for various age groups and delineate the defining features leading to a diagnosis of asthma.
- Define asthma groups by symptom severity and frequency based on current classification guidelines.
- Discuss the impact of risk factors, exacerbating factors, and chronic comorbidities on morbidity, treatment, and prognosis.
- List common asthma triggers and explain the importance of trigger avoidance and environmental controls in minimizing the frequency and severity of asthma exacerbations.
- State the basic pharmacology, safety profile, and potential adverse effects of commonly used medications, including bronchodilators, leukotriene modifiers, inhaled or systemic corticosteroids, and magnesium sulfate
- Compare and contrast indications for the use of high dose bronchodilator therapy via multiple meter dose inhaler or continuous nebulized albuterol.
- Describe the different formulations of systemic corticosteroids commonly used for treatment of acute asthma exacerbation and the indications for each.
- Describe the utility of alternate therapies such as magnesium sulfate for acute refractory asthma.
- Cite the common complications of asthma or asthma treatment, including pneumothorax, atelectasis, lobar collapse, respiratory failure, poor cardiac output, dysrhythmias, and others.
- Describe the utility of using asthma management plans to both monitor and treat asthma via early symptom recognition, pulmonary function testing (spirometry and/or peak flow), and proper use of controller and reliever medications.
- Discuss the goals of asthma management, including the maintenance of normal activity levels (including physical activity, uninterrupted sleep, and school attendance) and pulmonary function; the prevention of chronic symptoms, recurrent exacerbations, and hospitalizations; and the provision of optimal pharmacotherapy, while minimizing adverse events.
- List specific indications for referral to an asthma subspecialist.
Skills
Pediatric hospitalists should be able to:
- Diagnose and correctly classify asthma by efficiently performing an accurate history and physical examination.
- Assess clinical findings to determine the need for hospitalization and the appropriate level of care.
- Direct an evidence-based treatment plan for status asthmaticus.
- Identify and respond to side effects associated with asthma medications.
- Order and interpret objective measures of pulmonary function, including peak flow monitoring and spirometry.
- Order and interpret results of basic diagnostic tools, such as chest radiograph, blood gas, and others as indicated.
- Order appropriate monitoring and correctly interpret monitor data.
- Provide supplemental oxygen therapy and advanced airway management as necessary.
- Recognize signs and symptoms of serious complications of asthma, including pneumothorax or impending respiratory failure.
- Facilitate an effective transfer to a tertiary care center or intensive care setting when appropriate.
- Assess disease severity and modify the daily medication regimen based upon accurate assessment of changes in disease state, both for inpatient management and transition to home.
- Assess psychosocial factors that may impact care plans and provide appropriate interventions, including support, education, and referral to available resources.
- Initiate asthma education for patients and the family/caregivers as soon after admission as possible, as appropriate for the clinical context.
- Create a discharge plan that can be expediently activated when appropriate.
- Coordinate care with the primary care provider with a plan inclusive of discharge medications, home instructions, and follow-up plans.
- Complete a written asthma action plan and use it to educate patients and the family/caregivers on trigger avoidance, medication adherence, and disease control.
Attitudes
Pediatric hospitalists should be able to:
- Reinforce the role and responsibility of patients and the family/caregivers regarding self-care, recognition of symptoms, and disease management.
- Realize responsibility for effective communication with patients, the family/caregivers, and healthcare providers regarding care plans.
- Engage in a multi-disciplinary approach to the prevention, diagnosis, and treatment of asthma, involving when appropriate, social workers or case managers, respiratory therapists, and subspecialists.
- Collaborate with primary care providers and subspecialists to ensure coordinated longitudinal care for children with asthma.
Systems Organization and Improvement
In order to improve efficiency and quality within their organizations, pediatric hospitalists should:
- Lead, coordinate, or participate in local and national initiatives to further the development and implementation of evidence-based clinical guidelines to promote effective resource utilization and improve quality of care for hospitalized children with asthma.
- Work with hospital administrators to implement and utilize performance feedback and quality improvement measures to assess outcomes of instituted guidelines for the management of inpatient asthma.
- Collaborate with primary care providers, subspecialists, social workers, and case managers to ensure a smooth transition to the outpatient setting, and to minimize the need for readmission.
1. U.S. Department of Health and Human Services, National Institutes of Health. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma (EPR-3). 2007 Edition. http://www.nhlbi.nih.gov/health-pro/guidelines/current/asthma-guidelines. Accessed August 22, 2019.
2. Jones BP, Fleming GM, Otillio JK, Asokan I, Arnold DH. Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit. J Asthma. 2016;53(6):607-617. https://doi.org/10.3109/02770903.2015.1067323.
3. Saglani S, Fleming L, Sonnappa S, and Bush A. Advances in the aetiology, management, and prevention of acute asthma attacks in children. Lancet Child Adol Health. 2019;3(5):354-364. https://doi.org/10.1016/S2352-4642(19)30025-2.
Introduction
Asthma is one of the most common, non-communicable, chronic childhood diseases. It is a leading cause of healthcare utilization resulting in a significant number of primary care visits, emergency room visits, and hospitalizations. It has direct impact on patient quality of life with a heavy financial burden to individuals and society. The prevalence of asthma continues to rise and is not equally distributed throughout the population, differing by sex, race, socioeconomic level, and geographic location. The Department of Health and Human Services (DHHS) recognizes the weight of asthma disease on our society, having directed the National Institute of Health to create evidence-based guidelines for asthma care. Additionally, the DHHS continues to recognize asthma as a key element of the Healthy People 2020 initiative with several specific health objectives related directly to inpatient management. Due to the chronic nature of this disease, pediatric hospitalists should not only treat acute exacerbations resulting in status asthmaticus, but also create or reaffirm long-term management plans.
Knowledge
Pediatric hospitalists should be able to:
- Discuss the pathophysiology of asthma addressing both bronchoconstrictive and inflammatory components, and state how each impact pharmacologic treatment choices.
- Compare and contrast the pathophysiology of asthma with other common small airway illnesses in children, such as bronchiolitis, viral pneumonia with bronchospasm, or chronic lung disease.
- Describe disparities in asthma prevalence by sex, race, socioeconomic level, and geographic location.
- Discuss the role psychosocial factors (such as housing, parental mental health, financial status, lack of health insurance, and others) play in the risk for exposure to allergens, non-compliance to medical regimens, and access to health care.
- List the differential diagnosis of wheezing for various age groups and delineate the defining features leading to a diagnosis of asthma.
- Define asthma groups by symptom severity and frequency based on current classification guidelines.
- Discuss the impact of risk factors, exacerbating factors, and chronic comorbidities on morbidity, treatment, and prognosis.
- List common asthma triggers and explain the importance of trigger avoidance and environmental controls in minimizing the frequency and severity of asthma exacerbations.
- State the basic pharmacology, safety profile, and potential adverse effects of commonly used medications, including bronchodilators, leukotriene modifiers, inhaled or systemic corticosteroids, and magnesium sulfate
- Compare and contrast indications for the use of high dose bronchodilator therapy via multiple meter dose inhaler or continuous nebulized albuterol.
- Describe the different formulations of systemic corticosteroids commonly used for treatment of acute asthma exacerbation and the indications for each.
- Describe the utility of alternate therapies such as magnesium sulfate for acute refractory asthma.
- Cite the common complications of asthma or asthma treatment, including pneumothorax, atelectasis, lobar collapse, respiratory failure, poor cardiac output, dysrhythmias, and others.
- Describe the utility of using asthma management plans to both monitor and treat asthma via early symptom recognition, pulmonary function testing (spirometry and/or peak flow), and proper use of controller and reliever medications.
- Discuss the goals of asthma management, including the maintenance of normal activity levels (including physical activity, uninterrupted sleep, and school attendance) and pulmonary function; the prevention of chronic symptoms, recurrent exacerbations, and hospitalizations; and the provision of optimal pharmacotherapy, while minimizing adverse events.
- List specific indications for referral to an asthma subspecialist.
Skills
Pediatric hospitalists should be able to:
- Diagnose and correctly classify asthma by efficiently performing an accurate history and physical examination.
- Assess clinical findings to determine the need for hospitalization and the appropriate level of care.
- Direct an evidence-based treatment plan for status asthmaticus.
- Identify and respond to side effects associated with asthma medications.
- Order and interpret objective measures of pulmonary function, including peak flow monitoring and spirometry.
- Order and interpret results of basic diagnostic tools, such as chest radiograph, blood gas, and others as indicated.
- Order appropriate monitoring and correctly interpret monitor data.
- Provide supplemental oxygen therapy and advanced airway management as necessary.
- Recognize signs and symptoms of serious complications of asthma, including pneumothorax or impending respiratory failure.
- Facilitate an effective transfer to a tertiary care center or intensive care setting when appropriate.
- Assess disease severity and modify the daily medication regimen based upon accurate assessment of changes in disease state, both for inpatient management and transition to home.
- Assess psychosocial factors that may impact care plans and provide appropriate interventions, including support, education, and referral to available resources.
- Initiate asthma education for patients and the family/caregivers as soon after admission as possible, as appropriate for the clinical context.
- Create a discharge plan that can be expediently activated when appropriate.
- Coordinate care with the primary care provider with a plan inclusive of discharge medications, home instructions, and follow-up plans.
- Complete a written asthma action plan and use it to educate patients and the family/caregivers on trigger avoidance, medication adherence, and disease control.
Attitudes
Pediatric hospitalists should be able to:
- Reinforce the role and responsibility of patients and the family/caregivers regarding self-care, recognition of symptoms, and disease management.
- Realize responsibility for effective communication with patients, the family/caregivers, and healthcare providers regarding care plans.
- Engage in a multi-disciplinary approach to the prevention, diagnosis, and treatment of asthma, involving when appropriate, social workers or case managers, respiratory therapists, and subspecialists.
- Collaborate with primary care providers and subspecialists to ensure coordinated longitudinal care for children with asthma.
Systems Organization and Improvement
In order to improve efficiency and quality within their organizations, pediatric hospitalists should:
- Lead, coordinate, or participate in local and national initiatives to further the development and implementation of evidence-based clinical guidelines to promote effective resource utilization and improve quality of care for hospitalized children with asthma.
- Work with hospital administrators to implement and utilize performance feedback and quality improvement measures to assess outcomes of instituted guidelines for the management of inpatient asthma.
- Collaborate with primary care providers, subspecialists, social workers, and case managers to ensure a smooth transition to the outpatient setting, and to minimize the need for readmission.
Introduction
Asthma is one of the most common, non-communicable, chronic childhood diseases. It is a leading cause of healthcare utilization resulting in a significant number of primary care visits, emergency room visits, and hospitalizations. It has direct impact on patient quality of life with a heavy financial burden to individuals and society. The prevalence of asthma continues to rise and is not equally distributed throughout the population, differing by sex, race, socioeconomic level, and geographic location. The Department of Health and Human Services (DHHS) recognizes the weight of asthma disease on our society, having directed the National Institute of Health to create evidence-based guidelines for asthma care. Additionally, the DHHS continues to recognize asthma as a key element of the Healthy People 2020 initiative with several specific health objectives related directly to inpatient management. Due to the chronic nature of this disease, pediatric hospitalists should not only treat acute exacerbations resulting in status asthmaticus, but also create or reaffirm long-term management plans.
Knowledge
Pediatric hospitalists should be able to:
- Discuss the pathophysiology of asthma addressing both bronchoconstrictive and inflammatory components, and state how each impact pharmacologic treatment choices.
- Compare and contrast the pathophysiology of asthma with other common small airway illnesses in children, such as bronchiolitis, viral pneumonia with bronchospasm, or chronic lung disease.
- Describe disparities in asthma prevalence by sex, race, socioeconomic level, and geographic location.
- Discuss the role psychosocial factors (such as housing, parental mental health, financial status, lack of health insurance, and others) play in the risk for exposure to allergens, non-compliance to medical regimens, and access to health care.
- List the differential diagnosis of wheezing for various age groups and delineate the defining features leading to a diagnosis of asthma.
- Define asthma groups by symptom severity and frequency based on current classification guidelines.
- Discuss the impact of risk factors, exacerbating factors, and chronic comorbidities on morbidity, treatment, and prognosis.
- List common asthma triggers and explain the importance of trigger avoidance and environmental controls in minimizing the frequency and severity of asthma exacerbations.
- State the basic pharmacology, safety profile, and potential adverse effects of commonly used medications, including bronchodilators, leukotriene modifiers, inhaled or systemic corticosteroids, and magnesium sulfate
- Compare and contrast indications for the use of high dose bronchodilator therapy via multiple meter dose inhaler or continuous nebulized albuterol.
- Describe the different formulations of systemic corticosteroids commonly used for treatment of acute asthma exacerbation and the indications for each.
- Describe the utility of alternate therapies such as magnesium sulfate for acute refractory asthma.
- Cite the common complications of asthma or asthma treatment, including pneumothorax, atelectasis, lobar collapse, respiratory failure, poor cardiac output, dysrhythmias, and others.
- Describe the utility of using asthma management plans to both monitor and treat asthma via early symptom recognition, pulmonary function testing (spirometry and/or peak flow), and proper use of controller and reliever medications.
- Discuss the goals of asthma management, including the maintenance of normal activity levels (including physical activity, uninterrupted sleep, and school attendance) and pulmonary function; the prevention of chronic symptoms, recurrent exacerbations, and hospitalizations; and the provision of optimal pharmacotherapy, while minimizing adverse events.
- List specific indications for referral to an asthma subspecialist.
Skills
Pediatric hospitalists should be able to:
- Diagnose and correctly classify asthma by efficiently performing an accurate history and physical examination.
- Assess clinical findings to determine the need for hospitalization and the appropriate level of care.
- Direct an evidence-based treatment plan for status asthmaticus.
- Identify and respond to side effects associated with asthma medications.
- Order and interpret objective measures of pulmonary function, including peak flow monitoring and spirometry.
- Order and interpret results of basic diagnostic tools, such as chest radiograph, blood gas, and others as indicated.
- Order appropriate monitoring and correctly interpret monitor data.
- Provide supplemental oxygen therapy and advanced airway management as necessary.
- Recognize signs and symptoms of serious complications of asthma, including pneumothorax or impending respiratory failure.
- Facilitate an effective transfer to a tertiary care center or intensive care setting when appropriate.
- Assess disease severity and modify the daily medication regimen based upon accurate assessment of changes in disease state, both for inpatient management and transition to home.
- Assess psychosocial factors that may impact care plans and provide appropriate interventions, including support, education, and referral to available resources.
- Initiate asthma education for patients and the family/caregivers as soon after admission as possible, as appropriate for the clinical context.
- Create a discharge plan that can be expediently activated when appropriate.
- Coordinate care with the primary care provider with a plan inclusive of discharge medications, home instructions, and follow-up plans.
- Complete a written asthma action plan and use it to educate patients and the family/caregivers on trigger avoidance, medication adherence, and disease control.
Attitudes
Pediatric hospitalists should be able to:
- Reinforce the role and responsibility of patients and the family/caregivers regarding self-care, recognition of symptoms, and disease management.
- Realize responsibility for effective communication with patients, the family/caregivers, and healthcare providers regarding care plans.
- Engage in a multi-disciplinary approach to the prevention, diagnosis, and treatment of asthma, involving when appropriate, social workers or case managers, respiratory therapists, and subspecialists.
- Collaborate with primary care providers and subspecialists to ensure coordinated longitudinal care for children with asthma.
Systems Organization and Improvement
In order to improve efficiency and quality within their organizations, pediatric hospitalists should:
- Lead, coordinate, or participate in local and national initiatives to further the development and implementation of evidence-based clinical guidelines to promote effective resource utilization and improve quality of care for hospitalized children with asthma.
- Work with hospital administrators to implement and utilize performance feedback and quality improvement measures to assess outcomes of instituted guidelines for the management of inpatient asthma.
- Collaborate with primary care providers, subspecialists, social workers, and case managers to ensure a smooth transition to the outpatient setting, and to minimize the need for readmission.
1. U.S. Department of Health and Human Services, National Institutes of Health. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma (EPR-3). 2007 Edition. http://www.nhlbi.nih.gov/health-pro/guidelines/current/asthma-guidelines. Accessed August 22, 2019.
2. Jones BP, Fleming GM, Otillio JK, Asokan I, Arnold DH. Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit. J Asthma. 2016;53(6):607-617. https://doi.org/10.3109/02770903.2015.1067323.
3. Saglani S, Fleming L, Sonnappa S, and Bush A. Advances in the aetiology, management, and prevention of acute asthma attacks in children. Lancet Child Adol Health. 2019;3(5):354-364. https://doi.org/10.1016/S2352-4642(19)30025-2.
1. U.S. Department of Health and Human Services, National Institutes of Health. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma (EPR-3). 2007 Edition. http://www.nhlbi.nih.gov/health-pro/guidelines/current/asthma-guidelines. Accessed August 22, 2019.
2. Jones BP, Fleming GM, Otillio JK, Asokan I, Arnold DH. Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit. J Asthma. 2016;53(6):607-617. https://doi.org/10.3109/02770903.2015.1067323.
3. Saglani S, Fleming L, Sonnappa S, and Bush A. Advances in the aetiology, management, and prevention of acute asthma attacks in children. Lancet Child Adol Health. 2019;3(5):354-364. https://doi.org/10.1016/S2352-4642(19)30025-2.
In‐Hospital Asthma Resource Utilization
Pediatric hospitalizations for obesity‐related conditions have doubled in the last decade, mirroring the trend of higher levels of childhood obesity in the United States.[1, 2, 3] Recent studies have demonstrated worsened pediatric in‐hospital outcomes, including mortality and increased resource utilization, for children with obesity across a range of diagnoses.[4, 5, 6, 7, 8, 9, 10] Although the mechanisms driving the association between obesity and in‐hospital outcomes are not fully known, for asthma it is believed that adipocytes expressing inflammatory markers create a low level of systemic inflammation, thereby increasing the severity of allergic‐type illnesses and decreasing the response to anti‐inflammatory medications, such as steroids.[11, 12, 13, 14, 15, 16, 17, 18] The relationship of obesity and in‐hospital asthma outcomes is of particular interest because status asthmaticus is the most common reason for admission in children aged 3 to 12 years, accounting for approximately 150,000 admissions (7.4% of all hospitalizations for children and adolescents) and $835 million in hospital costs annually.[19]
Few prior studies have examined the association of obesity and asthma outcomes in the in‐hospital setting. The studies examining this association have found patients with obesity to have a longer hospital length of stay (LOS) and increased hospital costs.[8, 9, 20] Obesity has also been associated with increased respiratory treatments and supplemental oxygen requirements.[20] Associations between obesity and admission rates from the emergency department (ED) for pediatric asthma have been inconsistent.[21, 22] Most of these prior studies had several limitations in identifying patients with obesity, including using weight‐for‐age percentiles or International Classification of Diseases, Ninth Revision (ICD‐9) codes, rather than body mass index (BMI) percentile for age, the currently recommended method.[23, 24, 25] Methods other than BMI have the potential to either underestimate obesity (ie, ICD‐9 codes)[26] or to confound weight with adiposity (ie, weight‐for‐age percentiles),[27] thereby skewing the primary exposure of interest.
In the present study, we sought to examine associations between obesity and in‐hospital outcomes for pediatric status asthmaticus using the currently endorsed method for identifying obesity in children, BMI percentile for age.[23, 24, 25] The outcomes of interest included a broad range of in‐hospital measures, including resource utilization (medication and radiology use), readmission rates, billed charges, and LOS. We hypothesize that obesity, due to its proinflammatory state, would result in increased LOS, increased resource utilization, and an increased readmission rate for children admitted with status asthmaticus.
METHODS
Data Sources
Data for this retrospective cross‐sectional study were obtained from 2 sources. First, we queried the Pediatric Health Information System (PHIS) administrative database, which draws information from multiple children's hospitals to identify patients at our 2 institutions of interest who met study criteria. The PHIS database also was used to collect patient demographic data. PHIS is an administrative database operated by Children's Hospital Association (Overland Park, KS) containing clinical and billing data from 43 tertiary care, freestanding children's hospitals, including data on 41 ICD‐9 diagnoses, billed charges, and LOS. Based on the primary diagnosis, PHIS assigns each discharge to an All Patient Refined‐Diagnosis Related Group (APR‐DRG v.24) (3M Health information Systems, St. Paul, MN). APR‐DRGs allow similar diagnoses to be grouped together.[28, 29] PHIS also uses ICD‐9 codes to identify patients with a complex chronic condition (CCC).[30, 31] CCCs are those conditions that can be reasonably expected to last at least 12 months (unless death intervenes) and to involve either several different organ systems or one system severely enough to require specialty pediatric care and probably some period of hospitalization in a tertiary care center.[30, 31] PHIS data quality is ensured through a collaborative effort of the participating hospitals, the Children's Hospital Association, and Truven Healthcare.
Second, standardized chart reviews were then performed to collect clinical data not found in PHIS: BMI, LOS in hours, and medications administered, including total number of albuterol treatments administered during both the admission and the associated preceding ED visit.
Study Setting and Participants
All admissions examined in this study were at Children's Mercy Hospitals. Children's Mercy Hospitals includes 2 separate hospitals: 1 hospital is a 354‐bed academic, tertiary care freestanding children's hospital located in Kansas City, Missouri; a second, smaller, 50‐bed freestanding hospital is located in Overland Park, Kansas. Both hospitals have pediatric emergency departments. Inclusion criteria included patients aged 5 to 17 years discharged for status asthmaticus (APR‐DRG 141) at Children's Mercy Hospital from October 1, 2011 to September 30, 2012, with a recorded BMI during the admission or within 30 days of the admission. Patients between the ages of 2 and 5 years old were not included because of the incidence of viral‐induced wheezing in this age group and therefore possible miscoding of the asthma diagnosis. Exclusion criteria included a concurrent diagnosis of a CCC or bacterial pneumonia because these conditions could alter LOS, resource utilization, and readmission rates independent of the subject's status asthmaticus. In addition, to account for differences in the amount of treatment given in the pre‐inpatient setting, patients not initially treated through the hospital's ED were excluded. For patients with multiple admissions during the study period for the same diagnosis, only the index admission was examined. The institutional review board at Children's Mercy Hospital approved this study with waiver of informed consent.
Study Definitions
BMI percentile for age was used as both a continuous and categorical predictor variable. As a categorical variable it was divided into 4 categories: underweight (BMI <5%), normal weight (BMI 5%84%), overweight (BMI 85%94%), and obese (BMI 95%).[23] Race was categorized non‐Hispanic white, non‐Hispanic black, and other. Other included Asian, Pacific Islander, American Indian, and other. Ethnicity was categorized as Hispanic and non‐Hispanic. Insurance categories included private (commercial or TRICARE), public (Medicaid and Title V), and other (uninsured, self‐pay, and other). Adjusted billed charges were calculated for each hospitalization. Adjusted billed charges are the billed charges adjusted by the US Centers of Medicare and Medicaid Services' price/wage index for the study site's location.[32, 33]
To compare albuterol of different delivery methods, albuterol equivalents were calculated. Based upon prior research demonstrating equal efficacy between albuterol administered by nebulizer and metered‐dose inhaler (MDI),[34] every 2.5 mg of albuterol administered by nebulizer was treated as equivalent to 2 sprays of albuterol (90 g/spray) administered by MDI. Therefore, albuterol 2.5 mg nebulized and 2 sprays of albuterol (90 g/spray) were each defined as 1 albuterol equivalent. To compare continuous administration of nebulized albuterol with intermittent administration of albuterol, the total milligrams of continuously nebulized albuterol were examined. Per protocol at the study site, 10 mg per hour of continuous albuterol are administered for patients 5 years and younger and, for children 6 years and older, 15 mg per hour of continuous albuterol are administered. Based upon milligrams of albuterol nebulized, 5‐year‐old subjects receiving an hour of continuous albuterol would equal 4 albuterol equivalents (or 4 treatments of nebulized albuterol 2.5 mg/treatment or 4 treatments of albuterol 90 g/spray 2 sprays/treatment); for patients 6 years and older, an hour of continuous albuterol would equal 6 albuterol equivalents (or 6 treatments of nebulized albuterol 2.5 mg/treatment or 6 treatments of albuterol 90 g/spray 2 sprays/treatment). The variable total albuterol was then created to include albuterol equivalents delivered by metered dose inhaler and as both single and continuous nebulized treatments.
Main Exposure
The main exposure of interest was BMI percentile for age.
Outcome Measures
The main outcome measure was inpatient LOS measured in hours. Secondary outcome measures included the total albuterol (in the inpatient setting as well as combined inpatient and ED settings) and the administration of intravenous IV fluids and intramuscular (IM) or IV systemic steroids. Other secondary measures included readmission for status asthmaticus during the study period, adjusted billed charges, and inpatient chest radiograph utilization.
Statistical Analyses
We summarized categorical variables with frequencies and percentages, and used [2] test across BMI categories. The non‐normal distribution of continuous dependent variables (LOS, number of albuterol treatments, billed charges) were summarized with medians and interquartile ranges (IQRs). Kruskal‐Wallis test was used to examine outcomes across BMI categories. For regression models, BMI percentile for age was divided into deciles and treated as a continuous predictor. Factors used in the regression models included age, gender, race, ethnicity, and insurance. Total albuterol received in the ED was also included in the model to adjust for differences in the amount of treatment received prior to admission. Incidence rate ratios were created using Poisson regression for continuous outcomes (LOS, billed charges, and number of albuterol equivalent treatments administered), and odds ratios were created using logistic regression for dichotomous outcomes. All statistical analyses were performed using IBM SPSS Statistics version 20 (IBM, Armonk, NY), and P values <0.05 were considered statistically significant.
RESULTS
Patient Characteristics
Of 788 patients admitted for status asthmaticus during the study period, 518 (65.7%) met inclusion criteria; 42 (5.3%) did not meet inclusion criteria due to lack of a documented BMI (Table 1). Most patients were normal weight (59.7%). Approximately one‐third (36.7%) were either overweight or obese. The median age was 8 years, with patients with obesity being significantly older than underweight patients (9 vs 7.5 years, P<0.001). The majority of patients were black/African American (56.9%) and non‐Hispanic (88.6%). The percentage of patients who were obese was higher in patients of other race (29.3%) than whites (20.2%) or blacks (16.3%) (P<0.05). Patients of Hispanic ethnicity had a higher rate of obesity compared to non‐Hispanic patients (37.3% vs 17.4%, P<0.01). There were no differences in BMI categories for insurance.
| Patient Characteristics | Total | Category of Body Mass Index Percentile for Age | ||||
|---|---|---|---|---|---|---|
| Underweight | Normal | Overweight | Obese | P* | ||
| ||||||
| Total patients, n (%) | 518 | 18 (3.5) | 310 (59.8) | 88 (17.0) | 102 (19.7) | |
| Age, y, median (IQR) | 8 (611) | 7.5 (5.89) | 8 (610) | 8 (610) | 9 (712) | <0.001 |
| Gender, n (%) | ||||||
| Male | 309 | 12 (3.9) | 184 (59.5) | 46 (14.9) | 67 (21.7) | 0.27 |
| Female | 209 | 6 (2.9) | 126 (60.3) | 42 (20.1) | 35 (16.7) | |
| Race, n (%) | ||||||
| Non‐Hispanic white | 124 | 8 (6.5) | 76 (61.3) | 15 (12.1) | 25 (20.2) | 0.021 |
| Non‐Hispanic black | 295 | 7 (2.4) | 182 (61.7) | 58 (19.7) | 48 (16.3) | |
| Other | 99 | 3 (3.0) | 52 (52.5) | 15 (15.2) | 29 (29.3) | |
| Ethnicity, n (%) | ||||||
| Hispanic | 59 | 1 (1.7) | 25 (42.4) | 11 (18.6) | 22 (37.3) | 0.002 |
| Non‐Hispanic | 459 | 17 (3.7) | 285 (62.1) | 77 (16.8) | 80 (17.4) | |
| Insurance, n (%) | ||||||
| Private | 163 | 10 (6.1) | 97 (59.5) | 28 (17.2) | 28 (17.2) | 0.48 |
| Public | 313 | 7 (2.2) | 190 (60.7) | 51 (16.3) | 65 (20.8) | |
| Other | 42 | 1 (2.4) | 23 (54.8) | 9 (21.4) | 9 (21.4) | |
LOS and Resource Utilization
The median LOS for all patients was approximately 1 day (Table 2). The median number of albuterol treatments in the inpatient setting was 14 (IQR, 824). When albuterol treatments given in the ED were included, the median number of treatments increased to 38 (IQR, 2848). Approximately one‐half of patients required supplemental oxygen, one‐third received IV fluids, and one‐fifth received either IV or IM steroids (with all but 1.6% of the remaining patients receiving oral steroids). Less than 5% of the study population received magnesium sulfate, epinephrine, required intensive care unit (ICU) admission, or were readmitted for status asthmaticus within 30 days. Approximately 15% of patients received a chest radiograph. The median adjusted billed charge was approximately $7,000. There were no differences in any of these outcomes by BMI category (P>0.05).
| Total | Body Mass Index Category | ||||
|---|---|---|---|---|---|
| Underweight | Normal | Overweight | Obese | ||
| |||||
| Total Patients, n (%) | 518 | 18 (3.5) | 310 (59.8) | 88 (17.0) | 102 (19.7) |
| LOS, h, median (IQR) | 26 (1841) | 41 (19.560.5) | 26 (1841) | 26 (19.2540) | 31 (1942) |
| Inpatient albuterol equivalents, median (IQR) | 14(824) | 19 (9.528) | 14 (824) | 14 (8.522) | 16 (824) |
| Total albuterol equivalents, median (IQR) | 38 (2848) | 34 (2734) | 36 (2848) | 37 (2849.5) | 40 (3052) |
| Adjusted billed charges, $, median (IQR) | 6,999.5 (52929258) | 7,457 (56048536) | 6876 (52379390) | 7056 (54099061) | 7198 (53319306) |
| All readmits, n (%) | 44 (8.5) | 2 (11.1) | 29 (9.4) | 7 (8.0) | 6 (5.9) |
| Readmits within 30 days, n (%) | 11 (2.1) | 1 (5.6) | 7 (2.3) | 1 (1.1) | 2 (2.0) |
| ICU admissions, n (%) | 24 (4.6) | 0 (0) | 13 (4.2) | 7 (8.0) | 4 (3.9) |
| Chest radiograph, n (%) | 64 (12.4) | 5 (27.8) | 34 (11.0) | 12 (13.6) | 13 (12.7) |
| Oxygen, n (%) | 255 (49.2) | 11 (61.1) | 157 (50.6) | 42 (47.7) | 45 (44.1) |
| IV/IM steroid, n (%) | 93 (18.0) | 2 (11.1) | 53 (17.1) | 18 (20.5) | 20 (19.6) |
| Epinephrine, n (%) | 2 (0.4) | 0 (0) | 2 (0.6) | 0 (0) | 0 (0) |
| Magnesium, n (%) | 15 (2.9) | 0 (0) | 8 (2.6) | 3 (3.4) | 4 (3.9) |
| IV fluids, n (%) | 152 (29.3) | 4 (22.2) | 85 (27.4) | 31 (35.2) | 32 (31.4) |
Multivariable Results
After adjusting for age, gender, race, ethnicity, and insurance, the decile of BMI percentile for age showed a small negative association with LOS. Specifically, for each decile increase for BMI percentile for age, LOS decreased by approximately 2%. BMI percentile for age was not associated with other measures of resource utilization including total albuterol use, adjusted billed charges, readmission, ICU care, receipt of supplemental oxygen or a chest radiograph, IV fluids, or other medications (IV/IM steroids, epinephrine, or magnesium sulfate).
DISCUSSION
Our study suggests that the decile of BMI percentile for age is inversely associated with LOS but did not have a clinically meaningful effect. Secondary measures, such as total albuterol needs and adjusted billed charges, did not show an association with BMI percentile for age. There were also no associations between BMI percentile for age and other resource utilization outcomes.
Our findings differ from previous studies examining in‐hospital status asthmaticus in children who are overweight or obese. In addition, the present study was able to adjust for therapies received prior to admission. Carroll et al. demonstrated an increased LOS of approximately 3 days for overweight or obese asthmatics admitted to the ICU with status asthmaticus as well as increased duration of supplemental oxygen, continuous albuterol, and intravenous steroids.[20] It is possible that differences in methodology (ie, weight‐for‐age percentile vs BMI percentile for age, inclusion of ED treatments), different thresholds for treatment of status asthmaticus outside the ICU, or differences in patient populations studied (ie, only ICU patients vs all in‐hospital patients) explain the difference between their findings and the present study. The present study's use of BMI percentile for age follows current recommendations for classifying a patient as obese or overweight.[23, 24, 25] However, the use of classifications other than BMI percentile for age would tend to bias toward the null hypothesis, whereas in Carroll's study children who were overweight or obese had increased resource utilization. Additionally, in the time frame between this publication and the current study, many hospitals worked to standardize asthma hospitalizations by creating weaning protocols for albuterol, thereby decreasing LOS for all asthmatics, which may also affect the differences in LOS between groups of obese and nonobese patients.[35]
Woolford et al. found approximately a one‐half‐day increase in LOS and $2,000 higher mean charges for patients admitted with status asthmaticus and a secondary diagnosis of obesity.[8, 9] Study location and differing methods for defining obesity may account for the discrepancy between Woolford's findings and our study. We examined children admitted to the inpatient floor of a tertiary care children's hospital compared to Woolford et al.'s examination of pediatric patients admitted to all hospitals via the Kids' Inpatient Database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality). That study also relied on the coding of obesity as an ICD‐9 diagnosis, rather than examining the BMI of all admitted patients. Previous research has demonstrated that relying on a coded diagnosis of obesity is not as sensitive as measurement.[26] By relying on ICD‐9 diagnosis coding, only patients with very high BMIs may be diagnosed with obesity during the admission and therefore only associations between very high BMI and status asthmaticus will be examined.
There are several limitations to our findings. First, our study was limited to a single, tertiary care children's hospital and may not be generalizable to other hospitals. Our hospital standardizes the treatment of inpatient status asthmatics by formation of a respiratory care plan, involving interval scoring of respiratory symptoms and automatic spacing of albuterol treatments. This likely minimizes physician‐to‐physician variation. Second, we included only those patients who were initially treated within the ED associated with the admitting hospital to minimize the effects of timing for treatments prior to admittance. This excluded those patients first cared for by their primary care physician or by an outlying ED. Therefore, our sample may be biased toward a study population less connected to a medical home and therefore possibly poorer asthma control. Third, to utilize the most accurate method to define obesity, we excluded approximately 5% of eligible patients because BMI was unavailable. This may have included children with more severe asthma symptoms, as a height measurement may have been deferred due to their higher acuity. Asthma severity or chronicity would be associated with our outcomes of interest. However, we were unable to collect reliable data on severity or chronicity. Finally, to measure the amount of total albuterol needed by a patient during the ED and inpatient admissions, albuterol treatments delivered by MDI, nebulizer, or continuously were converted into total albuterol. Although based upon total milligram dosing and studies comparing routes of albuterol administration,[34] the validity of this conversion is unknown.
CONCLUSION
Although BMI percentile for age is inversely associated with LOS for in‐hospital pediatric status asthmaticus, the impact of BMI on this outcome likely is not clinically meaningful. Future investigations should examine other elements of BMI and in‐hospital status asthmaticus, such as any associations between BMI and admission rates.
Acknowledgements
The authors offer their appreciation to their research assistant, Amy Lee, for her support and dedication to this project.
Disclosures
Internal funds from Children's Mercy Hospital and Clinics supported the conduct of this work. The authors report no conflicts of interest.
- , , . Incidence of childhood obesity in the United States. N Engl J Med. 2014;370(5):403–411.
- , . Prevalence and trends in obesity and severe obesity among children in the United States, 1999–2012. JAMA Pediatr. 2014;168(6):561–566.
- , , , . Effects of childhood obesity on hospital care and costs, 1999–2005. Health Affairs. 2009;28(4):w751–w760.
- , , , , . Influence of obesity on clinical outcomes in hospitalized children: a systematic review. JAMA Pediatr. 2013;167(5):476–482.
- , . Appendicitis in the obese child. J Pediatr Surg. 2007;42(5):857–861.
- , , , , . Obesity: influence on length of hospital stay for the pediatric burn patient. J Burn Care Res. 2010;31(2):251–256.
- , , , , , . The impact of obesity on severely injured children and adolescents. J Pediatr Surg. 2006;41(1):88–91.
- , , , . Incremental hospital charges associated with obesity as a secondary diagnosis in children. Obesity (Silver Spring). 2007;15(7):1895–1901.
- , , , . Persistent gap of incremental charges for obesity as a secondary diagnosis in common pediatric hospitalizations. J Hosp Med. 2009;4(3):149–156.
- , , , . Resource utilization and expenditures for overweight and obese children. Arch Pediatr Adolesc Med. 2007;161(1):11–14.
- , , , , , . Decreased response to inhaled steroids in overweight and obese asthmatic children. J Allergy Clin Immunol. 2011;127(3):741–749.
- , , , , . Body mass and glucocorticoid response in asthma. Am J Respir Crit Care Med. 2008;178(7):682–687.
- , , , ; National Heart, Lung, and Blood Institute's Asthma Clinical Research Network. Body mass index and phenotype in subjects with mild‐to‐moderate persistent asthma. J Allergy Clin Immunol. 2009;123(6):1328–1334.e1.
- , . Obesity and asthma disease phenotypes. Curr Opin Allergy Clin Immunol. 2012;12(1):76–81.
- , . Obesity and the lung: 4. Obesity and asthma. Thorax. 2008;63(11):1018–1023.
- , , , et al. Body mass index and response to asthma therapy: fluticasone propionate/salmeterol versus montelukast. J Asthma. 2010;47(1):76–82.
- , , , et al. Effect of obesity on clinical presentation and response to treatment in asthma. J Asthma. 2006;43(7):553–558.
- , , , . Asthma and obesity in three‐year‐old urban children: role of sex and home environment. J Pediatr. 2011;159(1):14–20.
- , , , . Care of Children and Adolescents in U.S. Hospitals. Rockville, MD: Agency for Healthcare Research and Quality; 2003. Available at: http://archive.ahrq.gov/data/hcup/factbk4/factbk4.pdf. Accessed February 12, 2014.
- , , , . Childhood obesity increases duration of therapy during severe asthma exacerbations. Pediatr Crit Care Med. 2006;7(6):527–531.
- , , , , . Childhood overweight increases hospital admission rates for asthma. Pediatr. 2007;120(4):734–740.
- , , , . Body mass index and acute asthma severity among children presenting to the emergency department. Pediatr Allergy Immunol. 2009;21(3):480–488.
- Centers for Disease Control and Prevention. Basics about childhood obesity. Available at: http://www.cdc.gov/obesity/childhood/basics.html. Accessed February 12, 2014.
- . Screening and interventions for childhood overweight: a summary of evidence for the US Preventive Services Task Force. Pediatrics. 2005;116(1):e125–e144.
- ; Expert Committee. Expert committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report. Pediatrics. 2007;120(suppl 4):S164–S192.
- , , , . Comparison of ICD code‐based diagnosis of obesity with measured obesity in children and the implications for health care cost estimates. BMC Med Res Methodol. 2011;11(1):173.
- , ; American Academy of Pediatrics Committee on Nutrition. Prevention of pediatric overweight and obesity. Pediatrics. 2003;112(2):424–430.
- . Development of the 3M all patient‐refined diagnosis‐related groups (APR DRGs). Available at: http//www.ahrq.gov/legacy/qual/mortality/Hughes3.htm. Accessed March 1, 2014.
- . 3M Health Information Systems (HIS) APR‐DRG classification software: overview. Available at: http://www.ahrq.gov/legacy/qual/mortality/Hughessumm.htm. Accessed March 1, 2014.
- , , , , . Shifting place of death among children with complex chronic conditions in the United States, 1989–2003. JAMA. 2007;297(24):2725–2732.
- , , . Pediatric deaths attributable to complex chronic conditions: a population‐based study of Washington State, 1980–1997. Pediatrics. 2000;106(1 pt 2):205–209.
- , , , et al. Comparative effectiveness of pleural drainage procedures for the treatment of complicated pneumonia in childhood. J Hosp Med. 2011;6(5):256–263.
- , , , , , . Adjunct corticosteroids in children hospitalized with community‐acquired pneumonia. Pediatrics. 2011;127(2):e255–e263.
- , , . Holding chambers (spacers) versus nebulisers for beta‐agonist treatment of acute asthma. Cochrane Database Syst Rev. 2013;9:CD000052.
- , , , . Effectiveness of a clinical pathway for inpatient asthma management. Pediatrics. 2000;106(5):1006–1012.
Pediatric hospitalizations for obesity‐related conditions have doubled in the last decade, mirroring the trend of higher levels of childhood obesity in the United States.[1, 2, 3] Recent studies have demonstrated worsened pediatric in‐hospital outcomes, including mortality and increased resource utilization, for children with obesity across a range of diagnoses.[4, 5, 6, 7, 8, 9, 10] Although the mechanisms driving the association between obesity and in‐hospital outcomes are not fully known, for asthma it is believed that adipocytes expressing inflammatory markers create a low level of systemic inflammation, thereby increasing the severity of allergic‐type illnesses and decreasing the response to anti‐inflammatory medications, such as steroids.[11, 12, 13, 14, 15, 16, 17, 18] The relationship of obesity and in‐hospital asthma outcomes is of particular interest because status asthmaticus is the most common reason for admission in children aged 3 to 12 years, accounting for approximately 150,000 admissions (7.4% of all hospitalizations for children and adolescents) and $835 million in hospital costs annually.[19]
Few prior studies have examined the association of obesity and asthma outcomes in the in‐hospital setting. The studies examining this association have found patients with obesity to have a longer hospital length of stay (LOS) and increased hospital costs.[8, 9, 20] Obesity has also been associated with increased respiratory treatments and supplemental oxygen requirements.[20] Associations between obesity and admission rates from the emergency department (ED) for pediatric asthma have been inconsistent.[21, 22] Most of these prior studies had several limitations in identifying patients with obesity, including using weight‐for‐age percentiles or International Classification of Diseases, Ninth Revision (ICD‐9) codes, rather than body mass index (BMI) percentile for age, the currently recommended method.[23, 24, 25] Methods other than BMI have the potential to either underestimate obesity (ie, ICD‐9 codes)[26] or to confound weight with adiposity (ie, weight‐for‐age percentiles),[27] thereby skewing the primary exposure of interest.
In the present study, we sought to examine associations between obesity and in‐hospital outcomes for pediatric status asthmaticus using the currently endorsed method for identifying obesity in children, BMI percentile for age.[23, 24, 25] The outcomes of interest included a broad range of in‐hospital measures, including resource utilization (medication and radiology use), readmission rates, billed charges, and LOS. We hypothesize that obesity, due to its proinflammatory state, would result in increased LOS, increased resource utilization, and an increased readmission rate for children admitted with status asthmaticus.
METHODS
Data Sources
Data for this retrospective cross‐sectional study were obtained from 2 sources. First, we queried the Pediatric Health Information System (PHIS) administrative database, which draws information from multiple children's hospitals to identify patients at our 2 institutions of interest who met study criteria. The PHIS database also was used to collect patient demographic data. PHIS is an administrative database operated by Children's Hospital Association (Overland Park, KS) containing clinical and billing data from 43 tertiary care, freestanding children's hospitals, including data on 41 ICD‐9 diagnoses, billed charges, and LOS. Based on the primary diagnosis, PHIS assigns each discharge to an All Patient Refined‐Diagnosis Related Group (APR‐DRG v.24) (3M Health information Systems, St. Paul, MN). APR‐DRGs allow similar diagnoses to be grouped together.[28, 29] PHIS also uses ICD‐9 codes to identify patients with a complex chronic condition (CCC).[30, 31] CCCs are those conditions that can be reasonably expected to last at least 12 months (unless death intervenes) and to involve either several different organ systems or one system severely enough to require specialty pediatric care and probably some period of hospitalization in a tertiary care center.[30, 31] PHIS data quality is ensured through a collaborative effort of the participating hospitals, the Children's Hospital Association, and Truven Healthcare.
Second, standardized chart reviews were then performed to collect clinical data not found in PHIS: BMI, LOS in hours, and medications administered, including total number of albuterol treatments administered during both the admission and the associated preceding ED visit.
Study Setting and Participants
All admissions examined in this study were at Children's Mercy Hospitals. Children's Mercy Hospitals includes 2 separate hospitals: 1 hospital is a 354‐bed academic, tertiary care freestanding children's hospital located in Kansas City, Missouri; a second, smaller, 50‐bed freestanding hospital is located in Overland Park, Kansas. Both hospitals have pediatric emergency departments. Inclusion criteria included patients aged 5 to 17 years discharged for status asthmaticus (APR‐DRG 141) at Children's Mercy Hospital from October 1, 2011 to September 30, 2012, with a recorded BMI during the admission or within 30 days of the admission. Patients between the ages of 2 and 5 years old were not included because of the incidence of viral‐induced wheezing in this age group and therefore possible miscoding of the asthma diagnosis. Exclusion criteria included a concurrent diagnosis of a CCC or bacterial pneumonia because these conditions could alter LOS, resource utilization, and readmission rates independent of the subject's status asthmaticus. In addition, to account for differences in the amount of treatment given in the pre‐inpatient setting, patients not initially treated through the hospital's ED were excluded. For patients with multiple admissions during the study period for the same diagnosis, only the index admission was examined. The institutional review board at Children's Mercy Hospital approved this study with waiver of informed consent.
Study Definitions
BMI percentile for age was used as both a continuous and categorical predictor variable. As a categorical variable it was divided into 4 categories: underweight (BMI <5%), normal weight (BMI 5%84%), overweight (BMI 85%94%), and obese (BMI 95%).[23] Race was categorized non‐Hispanic white, non‐Hispanic black, and other. Other included Asian, Pacific Islander, American Indian, and other. Ethnicity was categorized as Hispanic and non‐Hispanic. Insurance categories included private (commercial or TRICARE), public (Medicaid and Title V), and other (uninsured, self‐pay, and other). Adjusted billed charges were calculated for each hospitalization. Adjusted billed charges are the billed charges adjusted by the US Centers of Medicare and Medicaid Services' price/wage index for the study site's location.[32, 33]
To compare albuterol of different delivery methods, albuterol equivalents were calculated. Based upon prior research demonstrating equal efficacy between albuterol administered by nebulizer and metered‐dose inhaler (MDI),[34] every 2.5 mg of albuterol administered by nebulizer was treated as equivalent to 2 sprays of albuterol (90 g/spray) administered by MDI. Therefore, albuterol 2.5 mg nebulized and 2 sprays of albuterol (90 g/spray) were each defined as 1 albuterol equivalent. To compare continuous administration of nebulized albuterol with intermittent administration of albuterol, the total milligrams of continuously nebulized albuterol were examined. Per protocol at the study site, 10 mg per hour of continuous albuterol are administered for patients 5 years and younger and, for children 6 years and older, 15 mg per hour of continuous albuterol are administered. Based upon milligrams of albuterol nebulized, 5‐year‐old subjects receiving an hour of continuous albuterol would equal 4 albuterol equivalents (or 4 treatments of nebulized albuterol 2.5 mg/treatment or 4 treatments of albuterol 90 g/spray 2 sprays/treatment); for patients 6 years and older, an hour of continuous albuterol would equal 6 albuterol equivalents (or 6 treatments of nebulized albuterol 2.5 mg/treatment or 6 treatments of albuterol 90 g/spray 2 sprays/treatment). The variable total albuterol was then created to include albuterol equivalents delivered by metered dose inhaler and as both single and continuous nebulized treatments.
Main Exposure
The main exposure of interest was BMI percentile for age.
Outcome Measures
The main outcome measure was inpatient LOS measured in hours. Secondary outcome measures included the total albuterol (in the inpatient setting as well as combined inpatient and ED settings) and the administration of intravenous IV fluids and intramuscular (IM) or IV systemic steroids. Other secondary measures included readmission for status asthmaticus during the study period, adjusted billed charges, and inpatient chest radiograph utilization.
Statistical Analyses
We summarized categorical variables with frequencies and percentages, and used [2] test across BMI categories. The non‐normal distribution of continuous dependent variables (LOS, number of albuterol treatments, billed charges) were summarized with medians and interquartile ranges (IQRs). Kruskal‐Wallis test was used to examine outcomes across BMI categories. For regression models, BMI percentile for age was divided into deciles and treated as a continuous predictor. Factors used in the regression models included age, gender, race, ethnicity, and insurance. Total albuterol received in the ED was also included in the model to adjust for differences in the amount of treatment received prior to admission. Incidence rate ratios were created using Poisson regression for continuous outcomes (LOS, billed charges, and number of albuterol equivalent treatments administered), and odds ratios were created using logistic regression for dichotomous outcomes. All statistical analyses were performed using IBM SPSS Statistics version 20 (IBM, Armonk, NY), and P values <0.05 were considered statistically significant.
RESULTS
Patient Characteristics
Of 788 patients admitted for status asthmaticus during the study period, 518 (65.7%) met inclusion criteria; 42 (5.3%) did not meet inclusion criteria due to lack of a documented BMI (Table 1). Most patients were normal weight (59.7%). Approximately one‐third (36.7%) were either overweight or obese. The median age was 8 years, with patients with obesity being significantly older than underweight patients (9 vs 7.5 years, P<0.001). The majority of patients were black/African American (56.9%) and non‐Hispanic (88.6%). The percentage of patients who were obese was higher in patients of other race (29.3%) than whites (20.2%) or blacks (16.3%) (P<0.05). Patients of Hispanic ethnicity had a higher rate of obesity compared to non‐Hispanic patients (37.3% vs 17.4%, P<0.01). There were no differences in BMI categories for insurance.
| Patient Characteristics | Total | Category of Body Mass Index Percentile for Age | ||||
|---|---|---|---|---|---|---|
| Underweight | Normal | Overweight | Obese | P* | ||
| ||||||
| Total patients, n (%) | 518 | 18 (3.5) | 310 (59.8) | 88 (17.0) | 102 (19.7) | |
| Age, y, median (IQR) | 8 (611) | 7.5 (5.89) | 8 (610) | 8 (610) | 9 (712) | <0.001 |
| Gender, n (%) | ||||||
| Male | 309 | 12 (3.9) | 184 (59.5) | 46 (14.9) | 67 (21.7) | 0.27 |
| Female | 209 | 6 (2.9) | 126 (60.3) | 42 (20.1) | 35 (16.7) | |
| Race, n (%) | ||||||
| Non‐Hispanic white | 124 | 8 (6.5) | 76 (61.3) | 15 (12.1) | 25 (20.2) | 0.021 |
| Non‐Hispanic black | 295 | 7 (2.4) | 182 (61.7) | 58 (19.7) | 48 (16.3) | |
| Other | 99 | 3 (3.0) | 52 (52.5) | 15 (15.2) | 29 (29.3) | |
| Ethnicity, n (%) | ||||||
| Hispanic | 59 | 1 (1.7) | 25 (42.4) | 11 (18.6) | 22 (37.3) | 0.002 |
| Non‐Hispanic | 459 | 17 (3.7) | 285 (62.1) | 77 (16.8) | 80 (17.4) | |
| Insurance, n (%) | ||||||
| Private | 163 | 10 (6.1) | 97 (59.5) | 28 (17.2) | 28 (17.2) | 0.48 |
| Public | 313 | 7 (2.2) | 190 (60.7) | 51 (16.3) | 65 (20.8) | |
| Other | 42 | 1 (2.4) | 23 (54.8) | 9 (21.4) | 9 (21.4) | |
LOS and Resource Utilization
The median LOS for all patients was approximately 1 day (Table 2). The median number of albuterol treatments in the inpatient setting was 14 (IQR, 824). When albuterol treatments given in the ED were included, the median number of treatments increased to 38 (IQR, 2848). Approximately one‐half of patients required supplemental oxygen, one‐third received IV fluids, and one‐fifth received either IV or IM steroids (with all but 1.6% of the remaining patients receiving oral steroids). Less than 5% of the study population received magnesium sulfate, epinephrine, required intensive care unit (ICU) admission, or were readmitted for status asthmaticus within 30 days. Approximately 15% of patients received a chest radiograph. The median adjusted billed charge was approximately $7,000. There were no differences in any of these outcomes by BMI category (P>0.05).
| Total | Body Mass Index Category | ||||
|---|---|---|---|---|---|
| Underweight | Normal | Overweight | Obese | ||
| |||||
| Total Patients, n (%) | 518 | 18 (3.5) | 310 (59.8) | 88 (17.0) | 102 (19.7) |
| LOS, h, median (IQR) | 26 (1841) | 41 (19.560.5) | 26 (1841) | 26 (19.2540) | 31 (1942) |
| Inpatient albuterol equivalents, median (IQR) | 14(824) | 19 (9.528) | 14 (824) | 14 (8.522) | 16 (824) |
| Total albuterol equivalents, median (IQR) | 38 (2848) | 34 (2734) | 36 (2848) | 37 (2849.5) | 40 (3052) |
| Adjusted billed charges, $, median (IQR) | 6,999.5 (52929258) | 7,457 (56048536) | 6876 (52379390) | 7056 (54099061) | 7198 (53319306) |
| All readmits, n (%) | 44 (8.5) | 2 (11.1) | 29 (9.4) | 7 (8.0) | 6 (5.9) |
| Readmits within 30 days, n (%) | 11 (2.1) | 1 (5.6) | 7 (2.3) | 1 (1.1) | 2 (2.0) |
| ICU admissions, n (%) | 24 (4.6) | 0 (0) | 13 (4.2) | 7 (8.0) | 4 (3.9) |
| Chest radiograph, n (%) | 64 (12.4) | 5 (27.8) | 34 (11.0) | 12 (13.6) | 13 (12.7) |
| Oxygen, n (%) | 255 (49.2) | 11 (61.1) | 157 (50.6) | 42 (47.7) | 45 (44.1) |
| IV/IM steroid, n (%) | 93 (18.0) | 2 (11.1) | 53 (17.1) | 18 (20.5) | 20 (19.6) |
| Epinephrine, n (%) | 2 (0.4) | 0 (0) | 2 (0.6) | 0 (0) | 0 (0) |
| Magnesium, n (%) | 15 (2.9) | 0 (0) | 8 (2.6) | 3 (3.4) | 4 (3.9) |
| IV fluids, n (%) | 152 (29.3) | 4 (22.2) | 85 (27.4) | 31 (35.2) | 32 (31.4) |
Multivariable Results
After adjusting for age, gender, race, ethnicity, and insurance, the decile of BMI percentile for age showed a small negative association with LOS. Specifically, for each decile increase for BMI percentile for age, LOS decreased by approximately 2%. BMI percentile for age was not associated with other measures of resource utilization including total albuterol use, adjusted billed charges, readmission, ICU care, receipt of supplemental oxygen or a chest radiograph, IV fluids, or other medications (IV/IM steroids, epinephrine, or magnesium sulfate).
DISCUSSION
Our study suggests that the decile of BMI percentile for age is inversely associated with LOS but did not have a clinically meaningful effect. Secondary measures, such as total albuterol needs and adjusted billed charges, did not show an association with BMI percentile for age. There were also no associations between BMI percentile for age and other resource utilization outcomes.
Our findings differ from previous studies examining in‐hospital status asthmaticus in children who are overweight or obese. In addition, the present study was able to adjust for therapies received prior to admission. Carroll et al. demonstrated an increased LOS of approximately 3 days for overweight or obese asthmatics admitted to the ICU with status asthmaticus as well as increased duration of supplemental oxygen, continuous albuterol, and intravenous steroids.[20] It is possible that differences in methodology (ie, weight‐for‐age percentile vs BMI percentile for age, inclusion of ED treatments), different thresholds for treatment of status asthmaticus outside the ICU, or differences in patient populations studied (ie, only ICU patients vs all in‐hospital patients) explain the difference between their findings and the present study. The present study's use of BMI percentile for age follows current recommendations for classifying a patient as obese or overweight.[23, 24, 25] However, the use of classifications other than BMI percentile for age would tend to bias toward the null hypothesis, whereas in Carroll's study children who were overweight or obese had increased resource utilization. Additionally, in the time frame between this publication and the current study, many hospitals worked to standardize asthma hospitalizations by creating weaning protocols for albuterol, thereby decreasing LOS for all asthmatics, which may also affect the differences in LOS between groups of obese and nonobese patients.[35]
Woolford et al. found approximately a one‐half‐day increase in LOS and $2,000 higher mean charges for patients admitted with status asthmaticus and a secondary diagnosis of obesity.[8, 9] Study location and differing methods for defining obesity may account for the discrepancy between Woolford's findings and our study. We examined children admitted to the inpatient floor of a tertiary care children's hospital compared to Woolford et al.'s examination of pediatric patients admitted to all hospitals via the Kids' Inpatient Database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality). That study also relied on the coding of obesity as an ICD‐9 diagnosis, rather than examining the BMI of all admitted patients. Previous research has demonstrated that relying on a coded diagnosis of obesity is not as sensitive as measurement.[26] By relying on ICD‐9 diagnosis coding, only patients with very high BMIs may be diagnosed with obesity during the admission and therefore only associations between very high BMI and status asthmaticus will be examined.
There are several limitations to our findings. First, our study was limited to a single, tertiary care children's hospital and may not be generalizable to other hospitals. Our hospital standardizes the treatment of inpatient status asthmatics by formation of a respiratory care plan, involving interval scoring of respiratory symptoms and automatic spacing of albuterol treatments. This likely minimizes physician‐to‐physician variation. Second, we included only those patients who were initially treated within the ED associated with the admitting hospital to minimize the effects of timing for treatments prior to admittance. This excluded those patients first cared for by their primary care physician or by an outlying ED. Therefore, our sample may be biased toward a study population less connected to a medical home and therefore possibly poorer asthma control. Third, to utilize the most accurate method to define obesity, we excluded approximately 5% of eligible patients because BMI was unavailable. This may have included children with more severe asthma symptoms, as a height measurement may have been deferred due to their higher acuity. Asthma severity or chronicity would be associated with our outcomes of interest. However, we were unable to collect reliable data on severity or chronicity. Finally, to measure the amount of total albuterol needed by a patient during the ED and inpatient admissions, albuterol treatments delivered by MDI, nebulizer, or continuously were converted into total albuterol. Although based upon total milligram dosing and studies comparing routes of albuterol administration,[34] the validity of this conversion is unknown.
CONCLUSION
Although BMI percentile for age is inversely associated with LOS for in‐hospital pediatric status asthmaticus, the impact of BMI on this outcome likely is not clinically meaningful. Future investigations should examine other elements of BMI and in‐hospital status asthmaticus, such as any associations between BMI and admission rates.
Acknowledgements
The authors offer their appreciation to their research assistant, Amy Lee, for her support and dedication to this project.
Disclosures
Internal funds from Children's Mercy Hospital and Clinics supported the conduct of this work. The authors report no conflicts of interest.
Pediatric hospitalizations for obesity‐related conditions have doubled in the last decade, mirroring the trend of higher levels of childhood obesity in the United States.[1, 2, 3] Recent studies have demonstrated worsened pediatric in‐hospital outcomes, including mortality and increased resource utilization, for children with obesity across a range of diagnoses.[4, 5, 6, 7, 8, 9, 10] Although the mechanisms driving the association between obesity and in‐hospital outcomes are not fully known, for asthma it is believed that adipocytes expressing inflammatory markers create a low level of systemic inflammation, thereby increasing the severity of allergic‐type illnesses and decreasing the response to anti‐inflammatory medications, such as steroids.[11, 12, 13, 14, 15, 16, 17, 18] The relationship of obesity and in‐hospital asthma outcomes is of particular interest because status asthmaticus is the most common reason for admission in children aged 3 to 12 years, accounting for approximately 150,000 admissions (7.4% of all hospitalizations for children and adolescents) and $835 million in hospital costs annually.[19]
Few prior studies have examined the association of obesity and asthma outcomes in the in‐hospital setting. The studies examining this association have found patients with obesity to have a longer hospital length of stay (LOS) and increased hospital costs.[8, 9, 20] Obesity has also been associated with increased respiratory treatments and supplemental oxygen requirements.[20] Associations between obesity and admission rates from the emergency department (ED) for pediatric asthma have been inconsistent.[21, 22] Most of these prior studies had several limitations in identifying patients with obesity, including using weight‐for‐age percentiles or International Classification of Diseases, Ninth Revision (ICD‐9) codes, rather than body mass index (BMI) percentile for age, the currently recommended method.[23, 24, 25] Methods other than BMI have the potential to either underestimate obesity (ie, ICD‐9 codes)[26] or to confound weight with adiposity (ie, weight‐for‐age percentiles),[27] thereby skewing the primary exposure of interest.
In the present study, we sought to examine associations between obesity and in‐hospital outcomes for pediatric status asthmaticus using the currently endorsed method for identifying obesity in children, BMI percentile for age.[23, 24, 25] The outcomes of interest included a broad range of in‐hospital measures, including resource utilization (medication and radiology use), readmission rates, billed charges, and LOS. We hypothesize that obesity, due to its proinflammatory state, would result in increased LOS, increased resource utilization, and an increased readmission rate for children admitted with status asthmaticus.
METHODS
Data Sources
Data for this retrospective cross‐sectional study were obtained from 2 sources. First, we queried the Pediatric Health Information System (PHIS) administrative database, which draws information from multiple children's hospitals to identify patients at our 2 institutions of interest who met study criteria. The PHIS database also was used to collect patient demographic data. PHIS is an administrative database operated by Children's Hospital Association (Overland Park, KS) containing clinical and billing data from 43 tertiary care, freestanding children's hospitals, including data on 41 ICD‐9 diagnoses, billed charges, and LOS. Based on the primary diagnosis, PHIS assigns each discharge to an All Patient Refined‐Diagnosis Related Group (APR‐DRG v.24) (3M Health information Systems, St. Paul, MN). APR‐DRGs allow similar diagnoses to be grouped together.[28, 29] PHIS also uses ICD‐9 codes to identify patients with a complex chronic condition (CCC).[30, 31] CCCs are those conditions that can be reasonably expected to last at least 12 months (unless death intervenes) and to involve either several different organ systems or one system severely enough to require specialty pediatric care and probably some period of hospitalization in a tertiary care center.[30, 31] PHIS data quality is ensured through a collaborative effort of the participating hospitals, the Children's Hospital Association, and Truven Healthcare.
Second, standardized chart reviews were then performed to collect clinical data not found in PHIS: BMI, LOS in hours, and medications administered, including total number of albuterol treatments administered during both the admission and the associated preceding ED visit.
Study Setting and Participants
All admissions examined in this study were at Children's Mercy Hospitals. Children's Mercy Hospitals includes 2 separate hospitals: 1 hospital is a 354‐bed academic, tertiary care freestanding children's hospital located in Kansas City, Missouri; a second, smaller, 50‐bed freestanding hospital is located in Overland Park, Kansas. Both hospitals have pediatric emergency departments. Inclusion criteria included patients aged 5 to 17 years discharged for status asthmaticus (APR‐DRG 141) at Children's Mercy Hospital from October 1, 2011 to September 30, 2012, with a recorded BMI during the admission or within 30 days of the admission. Patients between the ages of 2 and 5 years old were not included because of the incidence of viral‐induced wheezing in this age group and therefore possible miscoding of the asthma diagnosis. Exclusion criteria included a concurrent diagnosis of a CCC or bacterial pneumonia because these conditions could alter LOS, resource utilization, and readmission rates independent of the subject's status asthmaticus. In addition, to account for differences in the amount of treatment given in the pre‐inpatient setting, patients not initially treated through the hospital's ED were excluded. For patients with multiple admissions during the study period for the same diagnosis, only the index admission was examined. The institutional review board at Children's Mercy Hospital approved this study with waiver of informed consent.
Study Definitions
BMI percentile for age was used as both a continuous and categorical predictor variable. As a categorical variable it was divided into 4 categories: underweight (BMI <5%), normal weight (BMI 5%84%), overweight (BMI 85%94%), and obese (BMI 95%).[23] Race was categorized non‐Hispanic white, non‐Hispanic black, and other. Other included Asian, Pacific Islander, American Indian, and other. Ethnicity was categorized as Hispanic and non‐Hispanic. Insurance categories included private (commercial or TRICARE), public (Medicaid and Title V), and other (uninsured, self‐pay, and other). Adjusted billed charges were calculated for each hospitalization. Adjusted billed charges are the billed charges adjusted by the US Centers of Medicare and Medicaid Services' price/wage index for the study site's location.[32, 33]
To compare albuterol of different delivery methods, albuterol equivalents were calculated. Based upon prior research demonstrating equal efficacy between albuterol administered by nebulizer and metered‐dose inhaler (MDI),[34] every 2.5 mg of albuterol administered by nebulizer was treated as equivalent to 2 sprays of albuterol (90 g/spray) administered by MDI. Therefore, albuterol 2.5 mg nebulized and 2 sprays of albuterol (90 g/spray) were each defined as 1 albuterol equivalent. To compare continuous administration of nebulized albuterol with intermittent administration of albuterol, the total milligrams of continuously nebulized albuterol were examined. Per protocol at the study site, 10 mg per hour of continuous albuterol are administered for patients 5 years and younger and, for children 6 years and older, 15 mg per hour of continuous albuterol are administered. Based upon milligrams of albuterol nebulized, 5‐year‐old subjects receiving an hour of continuous albuterol would equal 4 albuterol equivalents (or 4 treatments of nebulized albuterol 2.5 mg/treatment or 4 treatments of albuterol 90 g/spray 2 sprays/treatment); for patients 6 years and older, an hour of continuous albuterol would equal 6 albuterol equivalents (or 6 treatments of nebulized albuterol 2.5 mg/treatment or 6 treatments of albuterol 90 g/spray 2 sprays/treatment). The variable total albuterol was then created to include albuterol equivalents delivered by metered dose inhaler and as both single and continuous nebulized treatments.
Main Exposure
The main exposure of interest was BMI percentile for age.
Outcome Measures
The main outcome measure was inpatient LOS measured in hours. Secondary outcome measures included the total albuterol (in the inpatient setting as well as combined inpatient and ED settings) and the administration of intravenous IV fluids and intramuscular (IM) or IV systemic steroids. Other secondary measures included readmission for status asthmaticus during the study period, adjusted billed charges, and inpatient chest radiograph utilization.
Statistical Analyses
We summarized categorical variables with frequencies and percentages, and used [2] test across BMI categories. The non‐normal distribution of continuous dependent variables (LOS, number of albuterol treatments, billed charges) were summarized with medians and interquartile ranges (IQRs). Kruskal‐Wallis test was used to examine outcomes across BMI categories. For regression models, BMI percentile for age was divided into deciles and treated as a continuous predictor. Factors used in the regression models included age, gender, race, ethnicity, and insurance. Total albuterol received in the ED was also included in the model to adjust for differences in the amount of treatment received prior to admission. Incidence rate ratios were created using Poisson regression for continuous outcomes (LOS, billed charges, and number of albuterol equivalent treatments administered), and odds ratios were created using logistic regression for dichotomous outcomes. All statistical analyses were performed using IBM SPSS Statistics version 20 (IBM, Armonk, NY), and P values <0.05 were considered statistically significant.
RESULTS
Patient Characteristics
Of 788 patients admitted for status asthmaticus during the study period, 518 (65.7%) met inclusion criteria; 42 (5.3%) did not meet inclusion criteria due to lack of a documented BMI (Table 1). Most patients were normal weight (59.7%). Approximately one‐third (36.7%) were either overweight or obese. The median age was 8 years, with patients with obesity being significantly older than underweight patients (9 vs 7.5 years, P<0.001). The majority of patients were black/African American (56.9%) and non‐Hispanic (88.6%). The percentage of patients who were obese was higher in patients of other race (29.3%) than whites (20.2%) or blacks (16.3%) (P<0.05). Patients of Hispanic ethnicity had a higher rate of obesity compared to non‐Hispanic patients (37.3% vs 17.4%, P<0.01). There were no differences in BMI categories for insurance.
| Patient Characteristics | Total | Category of Body Mass Index Percentile for Age | ||||
|---|---|---|---|---|---|---|
| Underweight | Normal | Overweight | Obese | P* | ||
| ||||||
| Total patients, n (%) | 518 | 18 (3.5) | 310 (59.8) | 88 (17.0) | 102 (19.7) | |
| Age, y, median (IQR) | 8 (611) | 7.5 (5.89) | 8 (610) | 8 (610) | 9 (712) | <0.001 |
| Gender, n (%) | ||||||
| Male | 309 | 12 (3.9) | 184 (59.5) | 46 (14.9) | 67 (21.7) | 0.27 |
| Female | 209 | 6 (2.9) | 126 (60.3) | 42 (20.1) | 35 (16.7) | |
| Race, n (%) | ||||||
| Non‐Hispanic white | 124 | 8 (6.5) | 76 (61.3) | 15 (12.1) | 25 (20.2) | 0.021 |
| Non‐Hispanic black | 295 | 7 (2.4) | 182 (61.7) | 58 (19.7) | 48 (16.3) | |
| Other | 99 | 3 (3.0) | 52 (52.5) | 15 (15.2) | 29 (29.3) | |
| Ethnicity, n (%) | ||||||
| Hispanic | 59 | 1 (1.7) | 25 (42.4) | 11 (18.6) | 22 (37.3) | 0.002 |
| Non‐Hispanic | 459 | 17 (3.7) | 285 (62.1) | 77 (16.8) | 80 (17.4) | |
| Insurance, n (%) | ||||||
| Private | 163 | 10 (6.1) | 97 (59.5) | 28 (17.2) | 28 (17.2) | 0.48 |
| Public | 313 | 7 (2.2) | 190 (60.7) | 51 (16.3) | 65 (20.8) | |
| Other | 42 | 1 (2.4) | 23 (54.8) | 9 (21.4) | 9 (21.4) | |
LOS and Resource Utilization
The median LOS for all patients was approximately 1 day (Table 2). The median number of albuterol treatments in the inpatient setting was 14 (IQR, 824). When albuterol treatments given in the ED were included, the median number of treatments increased to 38 (IQR, 2848). Approximately one‐half of patients required supplemental oxygen, one‐third received IV fluids, and one‐fifth received either IV or IM steroids (with all but 1.6% of the remaining patients receiving oral steroids). Less than 5% of the study population received magnesium sulfate, epinephrine, required intensive care unit (ICU) admission, or were readmitted for status asthmaticus within 30 days. Approximately 15% of patients received a chest radiograph. The median adjusted billed charge was approximately $7,000. There were no differences in any of these outcomes by BMI category (P>0.05).
| Total | Body Mass Index Category | ||||
|---|---|---|---|---|---|
| Underweight | Normal | Overweight | Obese | ||
| |||||
| Total Patients, n (%) | 518 | 18 (3.5) | 310 (59.8) | 88 (17.0) | 102 (19.7) |
| LOS, h, median (IQR) | 26 (1841) | 41 (19.560.5) | 26 (1841) | 26 (19.2540) | 31 (1942) |
| Inpatient albuterol equivalents, median (IQR) | 14(824) | 19 (9.528) | 14 (824) | 14 (8.522) | 16 (824) |
| Total albuterol equivalents, median (IQR) | 38 (2848) | 34 (2734) | 36 (2848) | 37 (2849.5) | 40 (3052) |
| Adjusted billed charges, $, median (IQR) | 6,999.5 (52929258) | 7,457 (56048536) | 6876 (52379390) | 7056 (54099061) | 7198 (53319306) |
| All readmits, n (%) | 44 (8.5) | 2 (11.1) | 29 (9.4) | 7 (8.0) | 6 (5.9) |
| Readmits within 30 days, n (%) | 11 (2.1) | 1 (5.6) | 7 (2.3) | 1 (1.1) | 2 (2.0) |
| ICU admissions, n (%) | 24 (4.6) | 0 (0) | 13 (4.2) | 7 (8.0) | 4 (3.9) |
| Chest radiograph, n (%) | 64 (12.4) | 5 (27.8) | 34 (11.0) | 12 (13.6) | 13 (12.7) |
| Oxygen, n (%) | 255 (49.2) | 11 (61.1) | 157 (50.6) | 42 (47.7) | 45 (44.1) |
| IV/IM steroid, n (%) | 93 (18.0) | 2 (11.1) | 53 (17.1) | 18 (20.5) | 20 (19.6) |
| Epinephrine, n (%) | 2 (0.4) | 0 (0) | 2 (0.6) | 0 (0) | 0 (0) |
| Magnesium, n (%) | 15 (2.9) | 0 (0) | 8 (2.6) | 3 (3.4) | 4 (3.9) |
| IV fluids, n (%) | 152 (29.3) | 4 (22.2) | 85 (27.4) | 31 (35.2) | 32 (31.4) |
Multivariable Results
After adjusting for age, gender, race, ethnicity, and insurance, the decile of BMI percentile for age showed a small negative association with LOS. Specifically, for each decile increase for BMI percentile for age, LOS decreased by approximately 2%. BMI percentile for age was not associated with other measures of resource utilization including total albuterol use, adjusted billed charges, readmission, ICU care, receipt of supplemental oxygen or a chest radiograph, IV fluids, or other medications (IV/IM steroids, epinephrine, or magnesium sulfate).
DISCUSSION
Our study suggests that the decile of BMI percentile for age is inversely associated with LOS but did not have a clinically meaningful effect. Secondary measures, such as total albuterol needs and adjusted billed charges, did not show an association with BMI percentile for age. There were also no associations between BMI percentile for age and other resource utilization outcomes.
Our findings differ from previous studies examining in‐hospital status asthmaticus in children who are overweight or obese. In addition, the present study was able to adjust for therapies received prior to admission. Carroll et al. demonstrated an increased LOS of approximately 3 days for overweight or obese asthmatics admitted to the ICU with status asthmaticus as well as increased duration of supplemental oxygen, continuous albuterol, and intravenous steroids.[20] It is possible that differences in methodology (ie, weight‐for‐age percentile vs BMI percentile for age, inclusion of ED treatments), different thresholds for treatment of status asthmaticus outside the ICU, or differences in patient populations studied (ie, only ICU patients vs all in‐hospital patients) explain the difference between their findings and the present study. The present study's use of BMI percentile for age follows current recommendations for classifying a patient as obese or overweight.[23, 24, 25] However, the use of classifications other than BMI percentile for age would tend to bias toward the null hypothesis, whereas in Carroll's study children who were overweight or obese had increased resource utilization. Additionally, in the time frame between this publication and the current study, many hospitals worked to standardize asthma hospitalizations by creating weaning protocols for albuterol, thereby decreasing LOS for all asthmatics, which may also affect the differences in LOS between groups of obese and nonobese patients.[35]
Woolford et al. found approximately a one‐half‐day increase in LOS and $2,000 higher mean charges for patients admitted with status asthmaticus and a secondary diagnosis of obesity.[8, 9] Study location and differing methods for defining obesity may account for the discrepancy between Woolford's findings and our study. We examined children admitted to the inpatient floor of a tertiary care children's hospital compared to Woolford et al.'s examination of pediatric patients admitted to all hospitals via the Kids' Inpatient Database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality). That study also relied on the coding of obesity as an ICD‐9 diagnosis, rather than examining the BMI of all admitted patients. Previous research has demonstrated that relying on a coded diagnosis of obesity is not as sensitive as measurement.[26] By relying on ICD‐9 diagnosis coding, only patients with very high BMIs may be diagnosed with obesity during the admission and therefore only associations between very high BMI and status asthmaticus will be examined.
There are several limitations to our findings. First, our study was limited to a single, tertiary care children's hospital and may not be generalizable to other hospitals. Our hospital standardizes the treatment of inpatient status asthmatics by formation of a respiratory care plan, involving interval scoring of respiratory symptoms and automatic spacing of albuterol treatments. This likely minimizes physician‐to‐physician variation. Second, we included only those patients who were initially treated within the ED associated with the admitting hospital to minimize the effects of timing for treatments prior to admittance. This excluded those patients first cared for by their primary care physician or by an outlying ED. Therefore, our sample may be biased toward a study population less connected to a medical home and therefore possibly poorer asthma control. Third, to utilize the most accurate method to define obesity, we excluded approximately 5% of eligible patients because BMI was unavailable. This may have included children with more severe asthma symptoms, as a height measurement may have been deferred due to their higher acuity. Asthma severity or chronicity would be associated with our outcomes of interest. However, we were unable to collect reliable data on severity or chronicity. Finally, to measure the amount of total albuterol needed by a patient during the ED and inpatient admissions, albuterol treatments delivered by MDI, nebulizer, or continuously were converted into total albuterol. Although based upon total milligram dosing and studies comparing routes of albuterol administration,[34] the validity of this conversion is unknown.
CONCLUSION
Although BMI percentile for age is inversely associated with LOS for in‐hospital pediatric status asthmaticus, the impact of BMI on this outcome likely is not clinically meaningful. Future investigations should examine other elements of BMI and in‐hospital status asthmaticus, such as any associations between BMI and admission rates.
Acknowledgements
The authors offer their appreciation to their research assistant, Amy Lee, for her support and dedication to this project.
Disclosures
Internal funds from Children's Mercy Hospital and Clinics supported the conduct of this work. The authors report no conflicts of interest.
- , , . Incidence of childhood obesity in the United States. N Engl J Med. 2014;370(5):403–411.
- , . Prevalence and trends in obesity and severe obesity among children in the United States, 1999–2012. JAMA Pediatr. 2014;168(6):561–566.
- , , , . Effects of childhood obesity on hospital care and costs, 1999–2005. Health Affairs. 2009;28(4):w751–w760.
- , , , , . Influence of obesity on clinical outcomes in hospitalized children: a systematic review. JAMA Pediatr. 2013;167(5):476–482.
- , . Appendicitis in the obese child. J Pediatr Surg. 2007;42(5):857–861.
- , , , , . Obesity: influence on length of hospital stay for the pediatric burn patient. J Burn Care Res. 2010;31(2):251–256.
- , , , , , . The impact of obesity on severely injured children and adolescents. J Pediatr Surg. 2006;41(1):88–91.
- , , , . Incremental hospital charges associated with obesity as a secondary diagnosis in children. Obesity (Silver Spring). 2007;15(7):1895–1901.
- , , , . Persistent gap of incremental charges for obesity as a secondary diagnosis in common pediatric hospitalizations. J Hosp Med. 2009;4(3):149–156.
- , , , . Resource utilization and expenditures for overweight and obese children. Arch Pediatr Adolesc Med. 2007;161(1):11–14.
- , , , , , . Decreased response to inhaled steroids in overweight and obese asthmatic children. J Allergy Clin Immunol. 2011;127(3):741–749.
- , , , , . Body mass and glucocorticoid response in asthma. Am J Respir Crit Care Med. 2008;178(7):682–687.
- , , , ; National Heart, Lung, and Blood Institute's Asthma Clinical Research Network. Body mass index and phenotype in subjects with mild‐to‐moderate persistent asthma. J Allergy Clin Immunol. 2009;123(6):1328–1334.e1.
- , . Obesity and asthma disease phenotypes. Curr Opin Allergy Clin Immunol. 2012;12(1):76–81.
- , . Obesity and the lung: 4. Obesity and asthma. Thorax. 2008;63(11):1018–1023.
- , , , et al. Body mass index and response to asthma therapy: fluticasone propionate/salmeterol versus montelukast. J Asthma. 2010;47(1):76–82.
- , , , et al. Effect of obesity on clinical presentation and response to treatment in asthma. J Asthma. 2006;43(7):553–558.
- , , , . Asthma and obesity in three‐year‐old urban children: role of sex and home environment. J Pediatr. 2011;159(1):14–20.
- , , , . Care of Children and Adolescents in U.S. Hospitals. Rockville, MD: Agency for Healthcare Research and Quality; 2003. Available at: http://archive.ahrq.gov/data/hcup/factbk4/factbk4.pdf. Accessed February 12, 2014.
- , , , . Childhood obesity increases duration of therapy during severe asthma exacerbations. Pediatr Crit Care Med. 2006;7(6):527–531.
- , , , , . Childhood overweight increases hospital admission rates for asthma. Pediatr. 2007;120(4):734–740.
- , , , . Body mass index and acute asthma severity among children presenting to the emergency department. Pediatr Allergy Immunol. 2009;21(3):480–488.
- Centers for Disease Control and Prevention. Basics about childhood obesity. Available at: http://www.cdc.gov/obesity/childhood/basics.html. Accessed February 12, 2014.
- . Screening and interventions for childhood overweight: a summary of evidence for the US Preventive Services Task Force. Pediatrics. 2005;116(1):e125–e144.
- ; Expert Committee. Expert committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report. Pediatrics. 2007;120(suppl 4):S164–S192.
- , , , . Comparison of ICD code‐based diagnosis of obesity with measured obesity in children and the implications for health care cost estimates. BMC Med Res Methodol. 2011;11(1):173.
- , ; American Academy of Pediatrics Committee on Nutrition. Prevention of pediatric overweight and obesity. Pediatrics. 2003;112(2):424–430.
- . Development of the 3M all patient‐refined diagnosis‐related groups (APR DRGs). Available at: http//www.ahrq.gov/legacy/qual/mortality/Hughes3.htm. Accessed March 1, 2014.
- . 3M Health Information Systems (HIS) APR‐DRG classification software: overview. Available at: http://www.ahrq.gov/legacy/qual/mortality/Hughessumm.htm. Accessed March 1, 2014.
- , , , , . Shifting place of death among children with complex chronic conditions in the United States, 1989–2003. JAMA. 2007;297(24):2725–2732.
- , , . Pediatric deaths attributable to complex chronic conditions: a population‐based study of Washington State, 1980–1997. Pediatrics. 2000;106(1 pt 2):205–209.
- , , , et al. Comparative effectiveness of pleural drainage procedures for the treatment of complicated pneumonia in childhood. J Hosp Med. 2011;6(5):256–263.
- , , , , , . Adjunct corticosteroids in children hospitalized with community‐acquired pneumonia. Pediatrics. 2011;127(2):e255–e263.
- , , . Holding chambers (spacers) versus nebulisers for beta‐agonist treatment of acute asthma. Cochrane Database Syst Rev. 2013;9:CD000052.
- , , , . Effectiveness of a clinical pathway for inpatient asthma management. Pediatrics. 2000;106(5):1006–1012.
- , , . Incidence of childhood obesity in the United States. N Engl J Med. 2014;370(5):403–411.
- , . Prevalence and trends in obesity and severe obesity among children in the United States, 1999–2012. JAMA Pediatr. 2014;168(6):561–566.
- , , , . Effects of childhood obesity on hospital care and costs, 1999–2005. Health Affairs. 2009;28(4):w751–w760.
- , , , , . Influence of obesity on clinical outcomes in hospitalized children: a systematic review. JAMA Pediatr. 2013;167(5):476–482.
- , . Appendicitis in the obese child. J Pediatr Surg. 2007;42(5):857–861.
- , , , , . Obesity: influence on length of hospital stay for the pediatric burn patient. J Burn Care Res. 2010;31(2):251–256.
- , , , , , . The impact of obesity on severely injured children and adolescents. J Pediatr Surg. 2006;41(1):88–91.
- , , , . Incremental hospital charges associated with obesity as a secondary diagnosis in children. Obesity (Silver Spring). 2007;15(7):1895–1901.
- , , , . Persistent gap of incremental charges for obesity as a secondary diagnosis in common pediatric hospitalizations. J Hosp Med. 2009;4(3):149–156.
- , , , . Resource utilization and expenditures for overweight and obese children. Arch Pediatr Adolesc Med. 2007;161(1):11–14.
- , , , , , . Decreased response to inhaled steroids in overweight and obese asthmatic children. J Allergy Clin Immunol. 2011;127(3):741–749.
- , , , , . Body mass and glucocorticoid response in asthma. Am J Respir Crit Care Med. 2008;178(7):682–687.
- , , , ; National Heart, Lung, and Blood Institute's Asthma Clinical Research Network. Body mass index and phenotype in subjects with mild‐to‐moderate persistent asthma. J Allergy Clin Immunol. 2009;123(6):1328–1334.e1.
- , . Obesity and asthma disease phenotypes. Curr Opin Allergy Clin Immunol. 2012;12(1):76–81.
- , . Obesity and the lung: 4. Obesity and asthma. Thorax. 2008;63(11):1018–1023.
- , , , et al. Body mass index and response to asthma therapy: fluticasone propionate/salmeterol versus montelukast. J Asthma. 2010;47(1):76–82.
- , , , et al. Effect of obesity on clinical presentation and response to treatment in asthma. J Asthma. 2006;43(7):553–558.
- , , , . Asthma and obesity in three‐year‐old urban children: role of sex and home environment. J Pediatr. 2011;159(1):14–20.
- , , , . Care of Children and Adolescents in U.S. Hospitals. Rockville, MD: Agency for Healthcare Research and Quality; 2003. Available at: http://archive.ahrq.gov/data/hcup/factbk4/factbk4.pdf. Accessed February 12, 2014.
- , , , . Childhood obesity increases duration of therapy during severe asthma exacerbations. Pediatr Crit Care Med. 2006;7(6):527–531.
- , , , , . Childhood overweight increases hospital admission rates for asthma. Pediatr. 2007;120(4):734–740.
- , , , . Body mass index and acute asthma severity among children presenting to the emergency department. Pediatr Allergy Immunol. 2009;21(3):480–488.
- Centers for Disease Control and Prevention. Basics about childhood obesity. Available at: http://www.cdc.gov/obesity/childhood/basics.html. Accessed February 12, 2014.
- . Screening and interventions for childhood overweight: a summary of evidence for the US Preventive Services Task Force. Pediatrics. 2005;116(1):e125–e144.
- ; Expert Committee. Expert committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report. Pediatrics. 2007;120(suppl 4):S164–S192.
- , , , . Comparison of ICD code‐based diagnosis of obesity with measured obesity in children and the implications for health care cost estimates. BMC Med Res Methodol. 2011;11(1):173.
- , ; American Academy of Pediatrics Committee on Nutrition. Prevention of pediatric overweight and obesity. Pediatrics. 2003;112(2):424–430.
- . Development of the 3M all patient‐refined diagnosis‐related groups (APR DRGs). Available at: http//www.ahrq.gov/legacy/qual/mortality/Hughes3.htm. Accessed March 1, 2014.
- . 3M Health Information Systems (HIS) APR‐DRG classification software: overview. Available at: http://www.ahrq.gov/legacy/qual/mortality/Hughessumm.htm. Accessed March 1, 2014.
- , , , , . Shifting place of death among children with complex chronic conditions in the United States, 1989–2003. JAMA. 2007;297(24):2725–2732.
- , , . Pediatric deaths attributable to complex chronic conditions: a population‐based study of Washington State, 1980–1997. Pediatrics. 2000;106(1 pt 2):205–209.
- , , , et al. Comparative effectiveness of pleural drainage procedures for the treatment of complicated pneumonia in childhood. J Hosp Med. 2011;6(5):256–263.
- , , , , , . Adjunct corticosteroids in children hospitalized with community‐acquired pneumonia. Pediatrics. 2011;127(2):e255–e263.
- , , . Holding chambers (spacers) versus nebulisers for beta‐agonist treatment of acute asthma. Cochrane Database Syst Rev. 2013;9:CD000052.
- , , , . Effectiveness of a clinical pathway for inpatient asthma management. Pediatrics. 2000;106(5):1006–1012.
© 2014 Society of Hospital Medicine