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What are the causes of hypomagnesemia?
The causes of magnesium depletion and hypomagnesemia are decreased gastrointestinal (GI) absorption and increased renal loss. Decreased GI absorption is frequently due to diarrhea, malabsorption, and inadequate dietary intake. Common causes of excessive urinary loss are diuresis due to alcohol, glycosuria, and loop diuretics.
Medical conditions putting persons at high risk for hypomagnesemia are alcoholism, congestive heart failure, diabetes, chronic diarrhea, hypokalemia, hypocalcemia, and malnutrition (strength of recommendation: C, based on expert opinion, physiology, and case series). Evidence suggests that magnesium deficiency is both more common and more clinically significant than generally appreciated.
Evidence summary
Prevalence and incidence. In general, studies are limited by variations in analytic techniques and differences in defining the lower limit for normal serum magnesium.1 Estimates of the prevalence of hypomagnesemia in the general population range from 2.5% to 15%. A study of 11,000 white urban Americans aged 45 to 64 years (probability sampling) found 2.5% with magnesium <0.7 mmol/L and 5% with magnesium <0.75 mmol/L; rates for 4000 African Americans were twice as high.2
Some authors have proposed a higher range for normal serum magnesium, asserting that dietary magnesium deficiency is endemic in developed countries where acid rain reduces the magnesium content of crops and food processing causes further large reductions in the magnesium content of the diet.1 Moreover, common diseases are associated with hypomagnesemia and likely contaminate studies of “normal” populations. Thus, a study of 16,000 German subjects (including blood donors, outpatients, and children) found a 14.5% prevalence of hypomagnesemia using a lower limit of 0.76 mmol/L1; however, applying the more commonly cited lower limit of 0.70 mmol/L (1.7 mg/dL) to the same data yielded aprevalence of 2%.
Numerous studies agree that the prevalence of hypomagnesemia is much higher (10%–65%) in subpopulations defined by severity of illness (hospitalization, in intensive care unit [ICU] or pediatric ICU), increasing age (elderly/in nursing home), or specific diseases. For example, of 94 consecutive patients admitted to the ICU, 65% had hypomagnesemia.3 Likewise, for 127 consecutive patients admitted with a diagnosis of alcoholism, the prevalence was 30%.4
Because of limitations noted above, as well as the lack of control groups, the relative prevalence in these groups (compared with the general population) is uncertain, but the studies do identify high-risk populations. A single study, which included a control group, demonstrated an 11% prevalence of hypomagnesemia among 621 randomly selected hospitalized patients compared with 2.5% among 341 hospital employees.5 Other diseases associated with a high prevalence of hypomagnesemia include cardiovascular disease (hypertension, congestive heart failure, coronary artery disease), diabetes, diarrhea, diuretics use, hypokalemia, hypocalcemia, and malabsorption.6-9
Common causes. We found no high-quality studies to establish the relative probabilities of various causes in the general population or any subpopulation.10 The most common causes of significant hypomagnesemia in developed countries are said to be diabetes, alcoholism, and the use of diuretics. In a group of 5100 consecutive patients (predominantly outpatient, middle-aged, and female) presenting to a diagnostic lab, the most common diagnoses associated with hypomagnesemia were diabetes (20% of cases) and diuretic use (14% of cases); however, other potential causes, including alcoholism, were not identified.11 A complete list of causes is in the Table.
Serious causes. A critical serum magnesium level is less than 0.5 mmol/L and is associated with seizures and life-threatening arrhythmias.6 Very low magnesium levels typically result when an acute problem is superimposed on chronic depletion. For example, critical levels can occur among patients with diabetes during correction of ketoacidosis or alcoholics who develop vomiting, diarrhea, or pancreatitis.
Magnesium in the 0.5 to 0.7 mmol/L range may be life-threatening in certain disease contexts, such as acute myocardial infarction or congestive heart failure, where there is already a risk of fatal arrhythmia.8
Impact. The impact of hypomagnesemia is underestimated largely because clinicians fail to measure magnesium.12 Since magnesium is a cofactor for more than 300 enzymes and is involved in numerous transport mechanisms, it is not surprising that hypomagnesemia is associated with significant morbidity.
For example, in a study of 381 consecutive admissions at an inner-city hospital,13 approximately half the admissions went to ICUs and half to regular wards. Despite similar Acute Physiology and Chronic Health Evaluator (APACHE) scores at admission, hospital mortality was twice as high for hypomagnesemic patients in both care settings.
TABLE
Causes of hypomagnesemia
| Gastrointestinal |
| Diarrhea, dietary deficiency (including protein-calorie malnutrition, parenteral and enteral feeding with inadequate magnesium, alcoholism, and pregnancy), familial magnesium malabsorption, gastrointestinal fistulas, inflammatory bowel disease, laxative abuse, malabsorption (sprue, steatorrhea, chronic pancreatitis), nasogastric suction, surgical resection, vomiting |
| Renal |
| Alcoholism, diabetes, diuretics (thiazide, loop, and osmotic/hyperglycemia), other medications, hormones (hypoparathyroidism, hyperthyroidism, hyperaldosteronism, SIADH (syndrome of inappropriate antidiuretic hormone secretion), excessive vitamin D, ketoacidosis, renal disease (acute tubular necrosis, interstitial nephritis, glomerulonephritis, post-obstructive diuresis, post-renal transplantation), hypercalcemia/hypophosphatemia, tubular defects (primary magnesium wasting, Welt’s syndrome, Gitelman’s syndrome, renal tubular acidosis) |
| Shifts from extracellular to intracellular fluid |
| Acidosis (correction of), blood transfusions (massive), epinephrine, hungry bone syndrome, insulin/glucose/refeeding syndrome, pancreatitis (acute) |
| Transdermal losses |
| Excessive sweating, massive burns |
Recommendations from others
Several review articles include a comprehensive differential diagnosis for causes of magnesium deficiency based on physiologic principles as listed in the Table, but none provide data on the relative frequency of the various causes in the general population or specific subgroups.6-9
We need to know when magnesium replacement improves patient outcomes
John Hickner, MD, MSc
Department of Family Medicine, The University of Chicago Pritzker School of Medicine, Chicago, Ill
Treating the underlying cause of hypomagnesemia makes sense. However, even though clinicians often treat “the numbers,” it is not clear that magnesium replacement therapy is beneficial in the absence of symptoms caused by the hypomagnesemia. For example, hypomagnesemia is common for patients with acute myocardial infarction, but magnesium replacement therapy has not been shown to improve outcomes in 2 large randomized trials, the Fourth International Study of Infarct Survival (ISIS 4)14 and Magnesium in Coronaries (MAGIC).15 We need better-designed randomized trials to know for what clinical conditions magnesium replacement leads to improved patient-oriented outcomes.
1. Schimatschek HF, Rempis R. Prevalence of hypomagnesemia in an unselected German population of 16,000 individuals. Magnes Res 2001;14:283-290.
2. Ma J, Folsom AR, Melnick SL, et al. Associations of serum and dietary magnesium with cardiovascular disease, hypertension, diabetes, insulin, and carotid arterial wall thickness: the ARIC study. Atherosclerosis Risk in Communities Study. J Clin Epidemiol 1995;48:927-940.
3. Ryzen E, Wagers PW, Singer FR, Rude RK. Magnesium deficiency in a medical ICU population. Crit Care Med 1985;13:19-21.
4. Elisaf M, Merkouropoulos M, Tsianos EV, Siamopoulos KC. Pathogenic mechanisms of hypomagnesemia in alcoholic patients. J Trace Elem Med Biol 1995;9:210-214.
5. Wong ET, Rude RK, Singer FR, Shaw ST, Jr. A high prevalence of hypomagnesemia and hypermagnesemia in hospitalized patients. Am J Clin Pathol 1983;79:348-353.
6. Topf JM, Murray PT. Hypomagnesemia and hypermagnesemia. Rev Endocr Metab Disord 2003;4:195-206.
7. Whang R, Hampton EM, Whang DD. Magnesium homeostasis and clinical disorders of magnesium deficiency. Ann Pharmacother 1994;28:220-226.
8. Kelepouris E, Agus ZS. Hypomagnesemia: renal magnesium handling. Semin Nephrol 1998;18:58-73.
9. Dacey MJ. Hypomagnesemic disorders. Crit Care Clin 2001;17:155-173.
10. Richardson WS, Wilson MC, Guyatt GH, Cook DJ, Nishikawa J. Users’ Guides to the Medical Literature: XV. How to use an article about disease probability for differential diagnosis. Evidence-Based Medicine Working Group. JAMA 1999;281:1214-1219.
11. Jackson CE, Meier DW. Routine serum magnesium analysis. Correlation with clinical state in 5,100 patients. Ann Intern Med 1968;69:743-748.
12. Whang R, Ryder KW. Frequency of hypomagnesemia and hypermagnesemia. Requested vs routine. JAMA 1990;263:3063-3064.
13. Rubeiz GJ, Thill-Baharozian M, Hardie D, Carlson RW. Association of hypomagnesemia and mortality in acutely ill medical patients. Crit Care Med 1993;21:203-209.
14. ISIS-4 (Fourth International Study of Infarct Survival) Collaborative Group ISIS-4: a randomised factorial trial assessing early oral captopril, oral mononitrate, and intravenous magnesium sulphate in 58,050 patients with suspected acute myocardial infarction. Lancet 1995;345:669-685.
15. Magnesium in Coronaries (MAGIC) Trial Investigators. Early administration of intravenous magnesium to highrisk patients with acute myocardial infarction in the Magnesium in Coronaries (MAGIC) Trial: a randomised controlled trial. Lancet 2002;360:1189-1196.
The causes of magnesium depletion and hypomagnesemia are decreased gastrointestinal (GI) absorption and increased renal loss. Decreased GI absorption is frequently due to diarrhea, malabsorption, and inadequate dietary intake. Common causes of excessive urinary loss are diuresis due to alcohol, glycosuria, and loop diuretics.
Medical conditions putting persons at high risk for hypomagnesemia are alcoholism, congestive heart failure, diabetes, chronic diarrhea, hypokalemia, hypocalcemia, and malnutrition (strength of recommendation: C, based on expert opinion, physiology, and case series). Evidence suggests that magnesium deficiency is both more common and more clinically significant than generally appreciated.
Evidence summary
Prevalence and incidence. In general, studies are limited by variations in analytic techniques and differences in defining the lower limit for normal serum magnesium.1 Estimates of the prevalence of hypomagnesemia in the general population range from 2.5% to 15%. A study of 11,000 white urban Americans aged 45 to 64 years (probability sampling) found 2.5% with magnesium <0.7 mmol/L and 5% with magnesium <0.75 mmol/L; rates for 4000 African Americans were twice as high.2
Some authors have proposed a higher range for normal serum magnesium, asserting that dietary magnesium deficiency is endemic in developed countries where acid rain reduces the magnesium content of crops and food processing causes further large reductions in the magnesium content of the diet.1 Moreover, common diseases are associated with hypomagnesemia and likely contaminate studies of “normal” populations. Thus, a study of 16,000 German subjects (including blood donors, outpatients, and children) found a 14.5% prevalence of hypomagnesemia using a lower limit of 0.76 mmol/L1; however, applying the more commonly cited lower limit of 0.70 mmol/L (1.7 mg/dL) to the same data yielded aprevalence of 2%.
Numerous studies agree that the prevalence of hypomagnesemia is much higher (10%–65%) in subpopulations defined by severity of illness (hospitalization, in intensive care unit [ICU] or pediatric ICU), increasing age (elderly/in nursing home), or specific diseases. For example, of 94 consecutive patients admitted to the ICU, 65% had hypomagnesemia.3 Likewise, for 127 consecutive patients admitted with a diagnosis of alcoholism, the prevalence was 30%.4
Because of limitations noted above, as well as the lack of control groups, the relative prevalence in these groups (compared with the general population) is uncertain, but the studies do identify high-risk populations. A single study, which included a control group, demonstrated an 11% prevalence of hypomagnesemia among 621 randomly selected hospitalized patients compared with 2.5% among 341 hospital employees.5 Other diseases associated with a high prevalence of hypomagnesemia include cardiovascular disease (hypertension, congestive heart failure, coronary artery disease), diabetes, diarrhea, diuretics use, hypokalemia, hypocalcemia, and malabsorption.6-9
Common causes. We found no high-quality studies to establish the relative probabilities of various causes in the general population or any subpopulation.10 The most common causes of significant hypomagnesemia in developed countries are said to be diabetes, alcoholism, and the use of diuretics. In a group of 5100 consecutive patients (predominantly outpatient, middle-aged, and female) presenting to a diagnostic lab, the most common diagnoses associated with hypomagnesemia were diabetes (20% of cases) and diuretic use (14% of cases); however, other potential causes, including alcoholism, were not identified.11 A complete list of causes is in the Table.
Serious causes. A critical serum magnesium level is less than 0.5 mmol/L and is associated with seizures and life-threatening arrhythmias.6 Very low magnesium levels typically result when an acute problem is superimposed on chronic depletion. For example, critical levels can occur among patients with diabetes during correction of ketoacidosis or alcoholics who develop vomiting, diarrhea, or pancreatitis.
Magnesium in the 0.5 to 0.7 mmol/L range may be life-threatening in certain disease contexts, such as acute myocardial infarction or congestive heart failure, where there is already a risk of fatal arrhythmia.8
Impact. The impact of hypomagnesemia is underestimated largely because clinicians fail to measure magnesium.12 Since magnesium is a cofactor for more than 300 enzymes and is involved in numerous transport mechanisms, it is not surprising that hypomagnesemia is associated with significant morbidity.
For example, in a study of 381 consecutive admissions at an inner-city hospital,13 approximately half the admissions went to ICUs and half to regular wards. Despite similar Acute Physiology and Chronic Health Evaluator (APACHE) scores at admission, hospital mortality was twice as high for hypomagnesemic patients in both care settings.
TABLE
Causes of hypomagnesemia
| Gastrointestinal |
| Diarrhea, dietary deficiency (including protein-calorie malnutrition, parenteral and enteral feeding with inadequate magnesium, alcoholism, and pregnancy), familial magnesium malabsorption, gastrointestinal fistulas, inflammatory bowel disease, laxative abuse, malabsorption (sprue, steatorrhea, chronic pancreatitis), nasogastric suction, surgical resection, vomiting |
| Renal |
| Alcoholism, diabetes, diuretics (thiazide, loop, and osmotic/hyperglycemia), other medications, hormones (hypoparathyroidism, hyperthyroidism, hyperaldosteronism, SIADH (syndrome of inappropriate antidiuretic hormone secretion), excessive vitamin D, ketoacidosis, renal disease (acute tubular necrosis, interstitial nephritis, glomerulonephritis, post-obstructive diuresis, post-renal transplantation), hypercalcemia/hypophosphatemia, tubular defects (primary magnesium wasting, Welt’s syndrome, Gitelman’s syndrome, renal tubular acidosis) |
| Shifts from extracellular to intracellular fluid |
| Acidosis (correction of), blood transfusions (massive), epinephrine, hungry bone syndrome, insulin/glucose/refeeding syndrome, pancreatitis (acute) |
| Transdermal losses |
| Excessive sweating, massive burns |
Recommendations from others
Several review articles include a comprehensive differential diagnosis for causes of magnesium deficiency based on physiologic principles as listed in the Table, but none provide data on the relative frequency of the various causes in the general population or specific subgroups.6-9
We need to know when magnesium replacement improves patient outcomes
John Hickner, MD, MSc
Department of Family Medicine, The University of Chicago Pritzker School of Medicine, Chicago, Ill
Treating the underlying cause of hypomagnesemia makes sense. However, even though clinicians often treat “the numbers,” it is not clear that magnesium replacement therapy is beneficial in the absence of symptoms caused by the hypomagnesemia. For example, hypomagnesemia is common for patients with acute myocardial infarction, but magnesium replacement therapy has not been shown to improve outcomes in 2 large randomized trials, the Fourth International Study of Infarct Survival (ISIS 4)14 and Magnesium in Coronaries (MAGIC).15 We need better-designed randomized trials to know for what clinical conditions magnesium replacement leads to improved patient-oriented outcomes.
The causes of magnesium depletion and hypomagnesemia are decreased gastrointestinal (GI) absorption and increased renal loss. Decreased GI absorption is frequently due to diarrhea, malabsorption, and inadequate dietary intake. Common causes of excessive urinary loss are diuresis due to alcohol, glycosuria, and loop diuretics.
Medical conditions putting persons at high risk for hypomagnesemia are alcoholism, congestive heart failure, diabetes, chronic diarrhea, hypokalemia, hypocalcemia, and malnutrition (strength of recommendation: C, based on expert opinion, physiology, and case series). Evidence suggests that magnesium deficiency is both more common and more clinically significant than generally appreciated.
Evidence summary
Prevalence and incidence. In general, studies are limited by variations in analytic techniques and differences in defining the lower limit for normal serum magnesium.1 Estimates of the prevalence of hypomagnesemia in the general population range from 2.5% to 15%. A study of 11,000 white urban Americans aged 45 to 64 years (probability sampling) found 2.5% with magnesium <0.7 mmol/L and 5% with magnesium <0.75 mmol/L; rates for 4000 African Americans were twice as high.2
Some authors have proposed a higher range for normal serum magnesium, asserting that dietary magnesium deficiency is endemic in developed countries where acid rain reduces the magnesium content of crops and food processing causes further large reductions in the magnesium content of the diet.1 Moreover, common diseases are associated with hypomagnesemia and likely contaminate studies of “normal” populations. Thus, a study of 16,000 German subjects (including blood donors, outpatients, and children) found a 14.5% prevalence of hypomagnesemia using a lower limit of 0.76 mmol/L1; however, applying the more commonly cited lower limit of 0.70 mmol/L (1.7 mg/dL) to the same data yielded aprevalence of 2%.
Numerous studies agree that the prevalence of hypomagnesemia is much higher (10%–65%) in subpopulations defined by severity of illness (hospitalization, in intensive care unit [ICU] or pediatric ICU), increasing age (elderly/in nursing home), or specific diseases. For example, of 94 consecutive patients admitted to the ICU, 65% had hypomagnesemia.3 Likewise, for 127 consecutive patients admitted with a diagnosis of alcoholism, the prevalence was 30%.4
Because of limitations noted above, as well as the lack of control groups, the relative prevalence in these groups (compared with the general population) is uncertain, but the studies do identify high-risk populations. A single study, which included a control group, demonstrated an 11% prevalence of hypomagnesemia among 621 randomly selected hospitalized patients compared with 2.5% among 341 hospital employees.5 Other diseases associated with a high prevalence of hypomagnesemia include cardiovascular disease (hypertension, congestive heart failure, coronary artery disease), diabetes, diarrhea, diuretics use, hypokalemia, hypocalcemia, and malabsorption.6-9
Common causes. We found no high-quality studies to establish the relative probabilities of various causes in the general population or any subpopulation.10 The most common causes of significant hypomagnesemia in developed countries are said to be diabetes, alcoholism, and the use of diuretics. In a group of 5100 consecutive patients (predominantly outpatient, middle-aged, and female) presenting to a diagnostic lab, the most common diagnoses associated with hypomagnesemia were diabetes (20% of cases) and diuretic use (14% of cases); however, other potential causes, including alcoholism, were not identified.11 A complete list of causes is in the Table.
Serious causes. A critical serum magnesium level is less than 0.5 mmol/L and is associated with seizures and life-threatening arrhythmias.6 Very low magnesium levels typically result when an acute problem is superimposed on chronic depletion. For example, critical levels can occur among patients with diabetes during correction of ketoacidosis or alcoholics who develop vomiting, diarrhea, or pancreatitis.
Magnesium in the 0.5 to 0.7 mmol/L range may be life-threatening in certain disease contexts, such as acute myocardial infarction or congestive heart failure, where there is already a risk of fatal arrhythmia.8
Impact. The impact of hypomagnesemia is underestimated largely because clinicians fail to measure magnesium.12 Since magnesium is a cofactor for more than 300 enzymes and is involved in numerous transport mechanisms, it is not surprising that hypomagnesemia is associated with significant morbidity.
For example, in a study of 381 consecutive admissions at an inner-city hospital,13 approximately half the admissions went to ICUs and half to regular wards. Despite similar Acute Physiology and Chronic Health Evaluator (APACHE) scores at admission, hospital mortality was twice as high for hypomagnesemic patients in both care settings.
TABLE
Causes of hypomagnesemia
| Gastrointestinal |
| Diarrhea, dietary deficiency (including protein-calorie malnutrition, parenteral and enteral feeding with inadequate magnesium, alcoholism, and pregnancy), familial magnesium malabsorption, gastrointestinal fistulas, inflammatory bowel disease, laxative abuse, malabsorption (sprue, steatorrhea, chronic pancreatitis), nasogastric suction, surgical resection, vomiting |
| Renal |
| Alcoholism, diabetes, diuretics (thiazide, loop, and osmotic/hyperglycemia), other medications, hormones (hypoparathyroidism, hyperthyroidism, hyperaldosteronism, SIADH (syndrome of inappropriate antidiuretic hormone secretion), excessive vitamin D, ketoacidosis, renal disease (acute tubular necrosis, interstitial nephritis, glomerulonephritis, post-obstructive diuresis, post-renal transplantation), hypercalcemia/hypophosphatemia, tubular defects (primary magnesium wasting, Welt’s syndrome, Gitelman’s syndrome, renal tubular acidosis) |
| Shifts from extracellular to intracellular fluid |
| Acidosis (correction of), blood transfusions (massive), epinephrine, hungry bone syndrome, insulin/glucose/refeeding syndrome, pancreatitis (acute) |
| Transdermal losses |
| Excessive sweating, massive burns |
Recommendations from others
Several review articles include a comprehensive differential diagnosis for causes of magnesium deficiency based on physiologic principles as listed in the Table, but none provide data on the relative frequency of the various causes in the general population or specific subgroups.6-9
We need to know when magnesium replacement improves patient outcomes
John Hickner, MD, MSc
Department of Family Medicine, The University of Chicago Pritzker School of Medicine, Chicago, Ill
Treating the underlying cause of hypomagnesemia makes sense. However, even though clinicians often treat “the numbers,” it is not clear that magnesium replacement therapy is beneficial in the absence of symptoms caused by the hypomagnesemia. For example, hypomagnesemia is common for patients with acute myocardial infarction, but magnesium replacement therapy has not been shown to improve outcomes in 2 large randomized trials, the Fourth International Study of Infarct Survival (ISIS 4)14 and Magnesium in Coronaries (MAGIC).15 We need better-designed randomized trials to know for what clinical conditions magnesium replacement leads to improved patient-oriented outcomes.
1. Schimatschek HF, Rempis R. Prevalence of hypomagnesemia in an unselected German population of 16,000 individuals. Magnes Res 2001;14:283-290.
2. Ma J, Folsom AR, Melnick SL, et al. Associations of serum and dietary magnesium with cardiovascular disease, hypertension, diabetes, insulin, and carotid arterial wall thickness: the ARIC study. Atherosclerosis Risk in Communities Study. J Clin Epidemiol 1995;48:927-940.
3. Ryzen E, Wagers PW, Singer FR, Rude RK. Magnesium deficiency in a medical ICU population. Crit Care Med 1985;13:19-21.
4. Elisaf M, Merkouropoulos M, Tsianos EV, Siamopoulos KC. Pathogenic mechanisms of hypomagnesemia in alcoholic patients. J Trace Elem Med Biol 1995;9:210-214.
5. Wong ET, Rude RK, Singer FR, Shaw ST, Jr. A high prevalence of hypomagnesemia and hypermagnesemia in hospitalized patients. Am J Clin Pathol 1983;79:348-353.
6. Topf JM, Murray PT. Hypomagnesemia and hypermagnesemia. Rev Endocr Metab Disord 2003;4:195-206.
7. Whang R, Hampton EM, Whang DD. Magnesium homeostasis and clinical disorders of magnesium deficiency. Ann Pharmacother 1994;28:220-226.
8. Kelepouris E, Agus ZS. Hypomagnesemia: renal magnesium handling. Semin Nephrol 1998;18:58-73.
9. Dacey MJ. Hypomagnesemic disorders. Crit Care Clin 2001;17:155-173.
10. Richardson WS, Wilson MC, Guyatt GH, Cook DJ, Nishikawa J. Users’ Guides to the Medical Literature: XV. How to use an article about disease probability for differential diagnosis. Evidence-Based Medicine Working Group. JAMA 1999;281:1214-1219.
11. Jackson CE, Meier DW. Routine serum magnesium analysis. Correlation with clinical state in 5,100 patients. Ann Intern Med 1968;69:743-748.
12. Whang R, Ryder KW. Frequency of hypomagnesemia and hypermagnesemia. Requested vs routine. JAMA 1990;263:3063-3064.
13. Rubeiz GJ, Thill-Baharozian M, Hardie D, Carlson RW. Association of hypomagnesemia and mortality in acutely ill medical patients. Crit Care Med 1993;21:203-209.
14. ISIS-4 (Fourth International Study of Infarct Survival) Collaborative Group ISIS-4: a randomised factorial trial assessing early oral captopril, oral mononitrate, and intravenous magnesium sulphate in 58,050 patients with suspected acute myocardial infarction. Lancet 1995;345:669-685.
15. Magnesium in Coronaries (MAGIC) Trial Investigators. Early administration of intravenous magnesium to highrisk patients with acute myocardial infarction in the Magnesium in Coronaries (MAGIC) Trial: a randomised controlled trial. Lancet 2002;360:1189-1196.
1. Schimatschek HF, Rempis R. Prevalence of hypomagnesemia in an unselected German population of 16,000 individuals. Magnes Res 2001;14:283-290.
2. Ma J, Folsom AR, Melnick SL, et al. Associations of serum and dietary magnesium with cardiovascular disease, hypertension, diabetes, insulin, and carotid arterial wall thickness: the ARIC study. Atherosclerosis Risk in Communities Study. J Clin Epidemiol 1995;48:927-940.
3. Ryzen E, Wagers PW, Singer FR, Rude RK. Magnesium deficiency in a medical ICU population. Crit Care Med 1985;13:19-21.
4. Elisaf M, Merkouropoulos M, Tsianos EV, Siamopoulos KC. Pathogenic mechanisms of hypomagnesemia in alcoholic patients. J Trace Elem Med Biol 1995;9:210-214.
5. Wong ET, Rude RK, Singer FR, Shaw ST, Jr. A high prevalence of hypomagnesemia and hypermagnesemia in hospitalized patients. Am J Clin Pathol 1983;79:348-353.
6. Topf JM, Murray PT. Hypomagnesemia and hypermagnesemia. Rev Endocr Metab Disord 2003;4:195-206.
7. Whang R, Hampton EM, Whang DD. Magnesium homeostasis and clinical disorders of magnesium deficiency. Ann Pharmacother 1994;28:220-226.
8. Kelepouris E, Agus ZS. Hypomagnesemia: renal magnesium handling. Semin Nephrol 1998;18:58-73.
9. Dacey MJ. Hypomagnesemic disorders. Crit Care Clin 2001;17:155-173.
10. Richardson WS, Wilson MC, Guyatt GH, Cook DJ, Nishikawa J. Users’ Guides to the Medical Literature: XV. How to use an article about disease probability for differential diagnosis. Evidence-Based Medicine Working Group. JAMA 1999;281:1214-1219.
11. Jackson CE, Meier DW. Routine serum magnesium analysis. Correlation with clinical state in 5,100 patients. Ann Intern Med 1968;69:743-748.
12. Whang R, Ryder KW. Frequency of hypomagnesemia and hypermagnesemia. Requested vs routine. JAMA 1990;263:3063-3064.
13. Rubeiz GJ, Thill-Baharozian M, Hardie D, Carlson RW. Association of hypomagnesemia and mortality in acutely ill medical patients. Crit Care Med 1993;21:203-209.
14. ISIS-4 (Fourth International Study of Infarct Survival) Collaborative Group ISIS-4: a randomised factorial trial assessing early oral captopril, oral mononitrate, and intravenous magnesium sulphate in 58,050 patients with suspected acute myocardial infarction. Lancet 1995;345:669-685.
15. Magnesium in Coronaries (MAGIC) Trial Investigators. Early administration of intravenous magnesium to highrisk patients with acute myocardial infarction in the Magnesium in Coronaries (MAGIC) Trial: a randomised controlled trial. Lancet 2002;360:1189-1196.
Evidence-based answers from the Family Physicians Inquiries Network
Are antibiotics effective in preventing pneumonia for nursing home patients?
Antibiotics should not be used for prophylaxis of pneumonia in nursing homes. We found no studies testing the effectiveness of antibiotics in preventing pneumonia in any population, including persons with predisposing conditions such as influenza. Three measures effectively prevent pneumonia in nursing home patients: influenza vaccination of residents (strength of recommendation [SOR]: B, based on systematic review of homogenous cohort observational studies); influenza vaccination of caregivers (SOR: B, based on individual randomized controlled trial); pneumococcal vaccination of residents (SOR: B, based on randomized, nonblinded clinical trials and consistent case-control studies).
Two other suggested interventions have not been extensively tested: antiviral chemoprophylaxis during an influenza outbreak in the nursing home, and oral hygiene programs for nursing home residents.
Evidence summary
Overuse of antibiotics is already a problem in nursing homes. A large portion of bacterial pneumonia in the nursing home population results from aspiration of oropharyngeal bacteria, which is more likely to be drug-resistant if the resident has been on antibiotics.1 We found no studies that testing antibacterial agents for prevention of pneumonia in nursing home patients. However, 3 measures are clearly helpful in preventing pneumonia in nursing home patients:
- Influenza vaccination of residents: A meta-analysis of 20 cohort studies showed a 53% efficacy (95% confidence interval [CI], 35–66)—defined as 1 minus the odds ratio—for influenza immunization in preventing pneumonia.2
- Influenza vaccination of caregivers: A cluster randomized trial in British long-term care facilities demonstrated that influenza vaccination of health care workers (61% of 1078 workers) reduced the total nursing home mortality rate (odds ratio [OR]=0.56 [95% CI, 0.4–0.8]) for a drop in mortality rate from 17% to 10% (number needed to treat [NNT]=14.3).3
- Pneumococcal vaccination of residents: This evidence was reviewed in a prior Clinical Inquiry.4 The evidence comes primarily from 2 clinical trials in which the NNT to prevent 1 episode of pneumonia was about 35.
Two other proposed interventions require further study to evaluate their role in prophylaxis. Antiviral prophylaxis to prevent pneumonia during nursing home outbreaks of influenza has not been evaluated in controlled trials. Observational studies strongly suggest that amantadine, rimantadine, and oseltamivir are all effective in reducing spread of influenza during outbreaks in nursing homes (Table). Oseltamivir acts against influenza B as well as A and has fewer side effects, but it is more expensive.5,6 Presumably, decreasing the rate of influenza also reduces the rate of subsequent pneumonia.
Oral hygiene programs for nursing home residents may also reduce pneumonia. In a single study, 366 patients in 11 Japanese nursing homes were divided into controls (self-care) and those treated with rigorous oral care (by staff). The intervention group had a relative risk of 0.6 (95% CI, 0.36–0.99; NNT=12.5) for pneumonia over a 2-year period.7 The NNT for preventing a death by pneumonia was 11 (P<.01). This intriguing result merits follow up in larger groups in US nursing homes to see if this approach is feasible.
TABLE
Available treatment and prophylactic regimens for influenza
| Drug name | Regimen for treatment* | Regimen for prophylaxis† | Comments | Cost‡ |
|---|---|---|---|---|
| Oseltamivir (Tamiflu) | 75 mg orally twice daily for 5 days | 75 mg orally once daily for >7 days | Influenza A and B | 10 tabs $59.99 (no generic) |
| Rimantidine (Flumadine) | 100 mg orally twice daily (100 mg orally once daily in elderly) | 100 mg orally twice daily (100 mg orally once daily in elderly) | Influenza A only | 14 tabs $33.45 (no generic) |
| Amantadine (Symmetrel) | 100 mg orally twice daily (100 mg orally once daily in elderly) | 100 mg orally twice daily (100 mg orally once daily in elderly) | Influenza A only (consider lower doses in debilitated patients) | 60 tabs $75.58 (brand), $18.99 (generic) |
| Zanamivir (Relenza) | 2 inhalations (10 mg) every 12 hours for 5 days | Not indicated | Influenza A and B (inhalations may be difficult to administer to debilitated patients) | 20 inhalation doses $54.41 (no generic) |
| Source: Epocrates RX: Online and PDA-Based Reference, June 12, 2004. | ||||
| * Start treatment within 48 hours of onset of symptoms. | ||||
| † Start prophylaxis immediately or within 48 hours of exposure. | ||||
| ‡ Approximate retail price from www.drugstore.com, June 2004. | ||||
Recommendations from others
There are no recommendations about the use of antibiotic prophylaxis for pneumonia in either the nursing home or in the outpatient settings; however, there are clear recommendations against the overuse of antibiotics.8
The CDC Advisory Committee on Immunization Practices (ACIP) recommends:
- annual influenza vaccine for persons residing in nursing homes9
- annual influenza vaccine for health care workers in long-term care facilities9
- pneumococcal vaccine for persons residing in a nursing home (the schedule for an immunocompetent adult is a single dose, followed by a booster after age 65 if the first dose was before age 65, or after 5 years for persons <65 years with compromised immune status)10
- chemoprophylaxis for influenza outbreaks in nursing homes.11
Prevention is key for reducing pneumonia mortality
Jon O. Neher, MD
Valley Medical Center, Renton, Wash
Pneumonia is one of the most common causes of death for nursing home patients. While pneumonia can present with the classic fever, productive cough, and air hunger, it often presents with such nonspecific findings as altered mental status or mild tachypnea, which can significantly delay diagnosis. Additionally, many older adults poorly tolerate the metabolic demands of the disease and become critically ill very rapidly. Thus, prevention remains a key strategy for reducing mortality. Nursing home policies that facilitate vaccination and reduce disease transmission are critically important in this regard.
1. Yamaya M, Yanai M, Ohrui T, Arai H, Sasaki H. Interventions to prevent pneumonia among older adults. J Am Geriatr Soc 2001;49:85-90.
2. Gross PA, Hermogenes AW, Sacks HS, Lau J, Levandowski RA. The efficacy of influenza vaccine in elderly persons. A meta-analysis and review of the literature. Ann Intern Med 1995;123:518-527.
3. Potter J, Stott DJ, Roberts MA, et al. Influenza vaccination of health care workers in long-term-care hospitals reduces the mortality of elderly patients. J Infect Dis 1997;175:1-6.
4. McCormack O, Meza J, Martin S, Tatum P. Is pneumococcal vaccine effective in nursing home patients? J Fam Pract 2003;52:150-154.
5. Arden NH, Patriarca PA, Fasano MB, et al. The roles of vaccination and amantadine prophylaxis in controlling an outbreak of influenza A (H3N2) in a nursing home. Arch Intern Med 1988;148:865-868.
6. Parker R, Loewen N, Skowronski D. Experience with oseltamivir in the control of a nursing home influenza B outbreak. Can Commun Dis Rep 2001;27:37-40.
7. Yoneyama T, Yoshida M, Ohrui T, et al. Oral care reduces pneumonia in older patients in nursing homes. J Am Geriatr Soc 2002;50:430-433.
8. Strassbaugh LJ, Crossley KB, Nurse BA, Thrupp LD. Antimicrobial resistance in long-term care facilities. Infection Control and Hospital Epidemiology 1996;17:129-140.
9. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 1999;48(RR-4):1-28.
10. Prevention of Pneumococcal Disease: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 1997;46(RR-8):1-24.
11. Bridges CB, Fukuda K, Uyeki TM, Cox NJ, Singleton JA. Centers for Disease Control and Prevention, Advisory Committee on Immunization Practices. Prevention and Control of Influenza. Recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep 2002;51(RR-3):1-31.
Antibiotics should not be used for prophylaxis of pneumonia in nursing homes. We found no studies testing the effectiveness of antibiotics in preventing pneumonia in any population, including persons with predisposing conditions such as influenza. Three measures effectively prevent pneumonia in nursing home patients: influenza vaccination of residents (strength of recommendation [SOR]: B, based on systematic review of homogenous cohort observational studies); influenza vaccination of caregivers (SOR: B, based on individual randomized controlled trial); pneumococcal vaccination of residents (SOR: B, based on randomized, nonblinded clinical trials and consistent case-control studies).
Two other suggested interventions have not been extensively tested: antiviral chemoprophylaxis during an influenza outbreak in the nursing home, and oral hygiene programs for nursing home residents.
Evidence summary
Overuse of antibiotics is already a problem in nursing homes. A large portion of bacterial pneumonia in the nursing home population results from aspiration of oropharyngeal bacteria, which is more likely to be drug-resistant if the resident has been on antibiotics.1 We found no studies that testing antibacterial agents for prevention of pneumonia in nursing home patients. However, 3 measures are clearly helpful in preventing pneumonia in nursing home patients:
- Influenza vaccination of residents: A meta-analysis of 20 cohort studies showed a 53% efficacy (95% confidence interval [CI], 35–66)—defined as 1 minus the odds ratio—for influenza immunization in preventing pneumonia.2
- Influenza vaccination of caregivers: A cluster randomized trial in British long-term care facilities demonstrated that influenza vaccination of health care workers (61% of 1078 workers) reduced the total nursing home mortality rate (odds ratio [OR]=0.56 [95% CI, 0.4–0.8]) for a drop in mortality rate from 17% to 10% (number needed to treat [NNT]=14.3).3
- Pneumococcal vaccination of residents: This evidence was reviewed in a prior Clinical Inquiry.4 The evidence comes primarily from 2 clinical trials in which the NNT to prevent 1 episode of pneumonia was about 35.
Two other proposed interventions require further study to evaluate their role in prophylaxis. Antiviral prophylaxis to prevent pneumonia during nursing home outbreaks of influenza has not been evaluated in controlled trials. Observational studies strongly suggest that amantadine, rimantadine, and oseltamivir are all effective in reducing spread of influenza during outbreaks in nursing homes (Table). Oseltamivir acts against influenza B as well as A and has fewer side effects, but it is more expensive.5,6 Presumably, decreasing the rate of influenza also reduces the rate of subsequent pneumonia.
Oral hygiene programs for nursing home residents may also reduce pneumonia. In a single study, 366 patients in 11 Japanese nursing homes were divided into controls (self-care) and those treated with rigorous oral care (by staff). The intervention group had a relative risk of 0.6 (95% CI, 0.36–0.99; NNT=12.5) for pneumonia over a 2-year period.7 The NNT for preventing a death by pneumonia was 11 (P<.01). This intriguing result merits follow up in larger groups in US nursing homes to see if this approach is feasible.
TABLE
Available treatment and prophylactic regimens for influenza
| Drug name | Regimen for treatment* | Regimen for prophylaxis† | Comments | Cost‡ |
|---|---|---|---|---|
| Oseltamivir (Tamiflu) | 75 mg orally twice daily for 5 days | 75 mg orally once daily for >7 days | Influenza A and B | 10 tabs $59.99 (no generic) |
| Rimantidine (Flumadine) | 100 mg orally twice daily (100 mg orally once daily in elderly) | 100 mg orally twice daily (100 mg orally once daily in elderly) | Influenza A only | 14 tabs $33.45 (no generic) |
| Amantadine (Symmetrel) | 100 mg orally twice daily (100 mg orally once daily in elderly) | 100 mg orally twice daily (100 mg orally once daily in elderly) | Influenza A only (consider lower doses in debilitated patients) | 60 tabs $75.58 (brand), $18.99 (generic) |
| Zanamivir (Relenza) | 2 inhalations (10 mg) every 12 hours for 5 days | Not indicated | Influenza A and B (inhalations may be difficult to administer to debilitated patients) | 20 inhalation doses $54.41 (no generic) |
| Source: Epocrates RX: Online and PDA-Based Reference, June 12, 2004. | ||||
| * Start treatment within 48 hours of onset of symptoms. | ||||
| † Start prophylaxis immediately or within 48 hours of exposure. | ||||
| ‡ Approximate retail price from www.drugstore.com, June 2004. | ||||
Recommendations from others
There are no recommendations about the use of antibiotic prophylaxis for pneumonia in either the nursing home or in the outpatient settings; however, there are clear recommendations against the overuse of antibiotics.8
The CDC Advisory Committee on Immunization Practices (ACIP) recommends:
- annual influenza vaccine for persons residing in nursing homes9
- annual influenza vaccine for health care workers in long-term care facilities9
- pneumococcal vaccine for persons residing in a nursing home (the schedule for an immunocompetent adult is a single dose, followed by a booster after age 65 if the first dose was before age 65, or after 5 years for persons <65 years with compromised immune status)10
- chemoprophylaxis for influenza outbreaks in nursing homes.11
Prevention is key for reducing pneumonia mortality
Jon O. Neher, MD
Valley Medical Center, Renton, Wash
Pneumonia is one of the most common causes of death for nursing home patients. While pneumonia can present with the classic fever, productive cough, and air hunger, it often presents with such nonspecific findings as altered mental status or mild tachypnea, which can significantly delay diagnosis. Additionally, many older adults poorly tolerate the metabolic demands of the disease and become critically ill very rapidly. Thus, prevention remains a key strategy for reducing mortality. Nursing home policies that facilitate vaccination and reduce disease transmission are critically important in this regard.
Antibiotics should not be used for prophylaxis of pneumonia in nursing homes. We found no studies testing the effectiveness of antibiotics in preventing pneumonia in any population, including persons with predisposing conditions such as influenza. Three measures effectively prevent pneumonia in nursing home patients: influenza vaccination of residents (strength of recommendation [SOR]: B, based on systematic review of homogenous cohort observational studies); influenza vaccination of caregivers (SOR: B, based on individual randomized controlled trial); pneumococcal vaccination of residents (SOR: B, based on randomized, nonblinded clinical trials and consistent case-control studies).
Two other suggested interventions have not been extensively tested: antiviral chemoprophylaxis during an influenza outbreak in the nursing home, and oral hygiene programs for nursing home residents.
Evidence summary
Overuse of antibiotics is already a problem in nursing homes. A large portion of bacterial pneumonia in the nursing home population results from aspiration of oropharyngeal bacteria, which is more likely to be drug-resistant if the resident has been on antibiotics.1 We found no studies that testing antibacterial agents for prevention of pneumonia in nursing home patients. However, 3 measures are clearly helpful in preventing pneumonia in nursing home patients:
- Influenza vaccination of residents: A meta-analysis of 20 cohort studies showed a 53% efficacy (95% confidence interval [CI], 35–66)—defined as 1 minus the odds ratio—for influenza immunization in preventing pneumonia.2
- Influenza vaccination of caregivers: A cluster randomized trial in British long-term care facilities demonstrated that influenza vaccination of health care workers (61% of 1078 workers) reduced the total nursing home mortality rate (odds ratio [OR]=0.56 [95% CI, 0.4–0.8]) for a drop in mortality rate from 17% to 10% (number needed to treat [NNT]=14.3).3
- Pneumococcal vaccination of residents: This evidence was reviewed in a prior Clinical Inquiry.4 The evidence comes primarily from 2 clinical trials in which the NNT to prevent 1 episode of pneumonia was about 35.
Two other proposed interventions require further study to evaluate their role in prophylaxis. Antiviral prophylaxis to prevent pneumonia during nursing home outbreaks of influenza has not been evaluated in controlled trials. Observational studies strongly suggest that amantadine, rimantadine, and oseltamivir are all effective in reducing spread of influenza during outbreaks in nursing homes (Table). Oseltamivir acts against influenza B as well as A and has fewer side effects, but it is more expensive.5,6 Presumably, decreasing the rate of influenza also reduces the rate of subsequent pneumonia.
Oral hygiene programs for nursing home residents may also reduce pneumonia. In a single study, 366 patients in 11 Japanese nursing homes were divided into controls (self-care) and those treated with rigorous oral care (by staff). The intervention group had a relative risk of 0.6 (95% CI, 0.36–0.99; NNT=12.5) for pneumonia over a 2-year period.7 The NNT for preventing a death by pneumonia was 11 (P<.01). This intriguing result merits follow up in larger groups in US nursing homes to see if this approach is feasible.
TABLE
Available treatment and prophylactic regimens for influenza
| Drug name | Regimen for treatment* | Regimen for prophylaxis† | Comments | Cost‡ |
|---|---|---|---|---|
| Oseltamivir (Tamiflu) | 75 mg orally twice daily for 5 days | 75 mg orally once daily for >7 days | Influenza A and B | 10 tabs $59.99 (no generic) |
| Rimantidine (Flumadine) | 100 mg orally twice daily (100 mg orally once daily in elderly) | 100 mg orally twice daily (100 mg orally once daily in elderly) | Influenza A only | 14 tabs $33.45 (no generic) |
| Amantadine (Symmetrel) | 100 mg orally twice daily (100 mg orally once daily in elderly) | 100 mg orally twice daily (100 mg orally once daily in elderly) | Influenza A only (consider lower doses in debilitated patients) | 60 tabs $75.58 (brand), $18.99 (generic) |
| Zanamivir (Relenza) | 2 inhalations (10 mg) every 12 hours for 5 days | Not indicated | Influenza A and B (inhalations may be difficult to administer to debilitated patients) | 20 inhalation doses $54.41 (no generic) |
| Source: Epocrates RX: Online and PDA-Based Reference, June 12, 2004. | ||||
| * Start treatment within 48 hours of onset of symptoms. | ||||
| † Start prophylaxis immediately or within 48 hours of exposure. | ||||
| ‡ Approximate retail price from www.drugstore.com, June 2004. | ||||
Recommendations from others
There are no recommendations about the use of antibiotic prophylaxis for pneumonia in either the nursing home or in the outpatient settings; however, there are clear recommendations against the overuse of antibiotics.8
The CDC Advisory Committee on Immunization Practices (ACIP) recommends:
- annual influenza vaccine for persons residing in nursing homes9
- annual influenza vaccine for health care workers in long-term care facilities9
- pneumococcal vaccine for persons residing in a nursing home (the schedule for an immunocompetent adult is a single dose, followed by a booster after age 65 if the first dose was before age 65, or after 5 years for persons <65 years with compromised immune status)10
- chemoprophylaxis for influenza outbreaks in nursing homes.11
Prevention is key for reducing pneumonia mortality
Jon O. Neher, MD
Valley Medical Center, Renton, Wash
Pneumonia is one of the most common causes of death for nursing home patients. While pneumonia can present with the classic fever, productive cough, and air hunger, it often presents with such nonspecific findings as altered mental status or mild tachypnea, which can significantly delay diagnosis. Additionally, many older adults poorly tolerate the metabolic demands of the disease and become critically ill very rapidly. Thus, prevention remains a key strategy for reducing mortality. Nursing home policies that facilitate vaccination and reduce disease transmission are critically important in this regard.
1. Yamaya M, Yanai M, Ohrui T, Arai H, Sasaki H. Interventions to prevent pneumonia among older adults. J Am Geriatr Soc 2001;49:85-90.
2. Gross PA, Hermogenes AW, Sacks HS, Lau J, Levandowski RA. The efficacy of influenza vaccine in elderly persons. A meta-analysis and review of the literature. Ann Intern Med 1995;123:518-527.
3. Potter J, Stott DJ, Roberts MA, et al. Influenza vaccination of health care workers in long-term-care hospitals reduces the mortality of elderly patients. J Infect Dis 1997;175:1-6.
4. McCormack O, Meza J, Martin S, Tatum P. Is pneumococcal vaccine effective in nursing home patients? J Fam Pract 2003;52:150-154.
5. Arden NH, Patriarca PA, Fasano MB, et al. The roles of vaccination and amantadine prophylaxis in controlling an outbreak of influenza A (H3N2) in a nursing home. Arch Intern Med 1988;148:865-868.
6. Parker R, Loewen N, Skowronski D. Experience with oseltamivir in the control of a nursing home influenza B outbreak. Can Commun Dis Rep 2001;27:37-40.
7. Yoneyama T, Yoshida M, Ohrui T, et al. Oral care reduces pneumonia in older patients in nursing homes. J Am Geriatr Soc 2002;50:430-433.
8. Strassbaugh LJ, Crossley KB, Nurse BA, Thrupp LD. Antimicrobial resistance in long-term care facilities. Infection Control and Hospital Epidemiology 1996;17:129-140.
9. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 1999;48(RR-4):1-28.
10. Prevention of Pneumococcal Disease: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 1997;46(RR-8):1-24.
11. Bridges CB, Fukuda K, Uyeki TM, Cox NJ, Singleton JA. Centers for Disease Control and Prevention, Advisory Committee on Immunization Practices. Prevention and Control of Influenza. Recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep 2002;51(RR-3):1-31.
1. Yamaya M, Yanai M, Ohrui T, Arai H, Sasaki H. Interventions to prevent pneumonia among older adults. J Am Geriatr Soc 2001;49:85-90.
2. Gross PA, Hermogenes AW, Sacks HS, Lau J, Levandowski RA. The efficacy of influenza vaccine in elderly persons. A meta-analysis and review of the literature. Ann Intern Med 1995;123:518-527.
3. Potter J, Stott DJ, Roberts MA, et al. Influenza vaccination of health care workers in long-term-care hospitals reduces the mortality of elderly patients. J Infect Dis 1997;175:1-6.
4. McCormack O, Meza J, Martin S, Tatum P. Is pneumococcal vaccine effective in nursing home patients? J Fam Pract 2003;52:150-154.
5. Arden NH, Patriarca PA, Fasano MB, et al. The roles of vaccination and amantadine prophylaxis in controlling an outbreak of influenza A (H3N2) in a nursing home. Arch Intern Med 1988;148:865-868.
6. Parker R, Loewen N, Skowronski D. Experience with oseltamivir in the control of a nursing home influenza B outbreak. Can Commun Dis Rep 2001;27:37-40.
7. Yoneyama T, Yoshida M, Ohrui T, et al. Oral care reduces pneumonia in older patients in nursing homes. J Am Geriatr Soc 2002;50:430-433.
8. Strassbaugh LJ, Crossley KB, Nurse BA, Thrupp LD. Antimicrobial resistance in long-term care facilities. Infection Control and Hospital Epidemiology 1996;17:129-140.
9. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 1999;48(RR-4):1-28.
10. Prevention of Pneumococcal Disease: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 1997;46(RR-8):1-24.
11. Bridges CB, Fukuda K, Uyeki TM, Cox NJ, Singleton JA. Centers for Disease Control and Prevention, Advisory Committee on Immunization Practices. Prevention and Control of Influenza. Recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep 2002;51(RR-3):1-31.
Evidence-based answers from the Family Physicians Inquiries Network