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Hyponatremia in Hospitalized Nursing Home Residents and Outcome: Minimize Hospitalization and Keep the Stay Short!
JAMDA 13 (2012) e8ee9
JAMDA journal homepage: www.jamda.com
Letter to the Editor
Hyponatremia in Hospitalized Nursing Home Residents and Outcome: Minimize Hospitalization and Keep the Stay Short! To the Editor: Hyponatremia, defined as serum sodium (Na) <135 mEq/L is a common electrolyte abnormality resulting from illness or medication use, and is associated with morbidity and mortality.1,2 The etiology of hyponatremia, the time taken to determine the etiology and the speed of correction may all contribute to outcome. Often, hyponatremia, a condition where body water can be normal, decreased or increased, is confused with disorders of clinical dehydration and its treatment.3,4 This pilot study examined whether the general characteristics of nursing home (NH) and community (C) patients, length of hospitalization (LOS), changes in serum Na ([ or Y) during hospitalization, existing comorbidity and manifestations might be risk factors for adverse outcome in hyponatremia. Since diuretics as a drug class clearly influence sodium and water metabolism, the impact of diuretics at admission or during hospitalization was also examined. Methods Data were collected during 2008, on 244 patients with hyponatremia or on diuretics at admission. Medical history, comorbidity, medications prescribed during hospitalization, manifestations, laboratory results and outcomes were recorded. For this analysis, adverse outcome was defined as any combination of (1) death, (2) alteration in mentation (drowsiness, stupor, coma), (3) seizures, (4) lethargy or weakness, and (5) muscle cramps.
risk of having a serum Na <135 mEq/L at admission increased by 10% for every 1-year increase in age (>30 years) (P < .0005) and, independently, by 43-fold in NH compared to C residents (P < .0005). Further, hyponatremia occurred significantly more often in African Americans (P ¼ .001) but less often in Hispanics (P ¼ .004) compared to White and Asian patients. Patient gender was found to be unrelated to hyponatremia at admission. A second analysis determined that the risk of having a serum Na <125 mEq/L at admission was 16-fold more likely in NH than community adults (P ¼ .002) but that age, gender, and race were not factors. Table 2 summarizes results of testing for risk factors for adverse outcome (defined above) or death during hospitalization. In this sample, the risk of adverse outcome was 72% less likely in males than females (P ¼ .009) but increased by 4.2-fold in patients with decreasing serum Na during hospitalization (P ¼ .027). Age, race, place of residence and LOS were determined not to be factors contributing to the risk of adverse outcome. A separate analysis that tested for risk factors for death during hospital stay determined a 23% increased risk of death for every 1-year increase in age (>30 years) (P ¼ .048) but that sex, place of residence (NH versus C), race, hyponatremia at admission, decreasing Na during hospitalization and LOS were unrelated. Diuretics were used by 28% of patients in the sample (12% thiazides, 14% furosemide, 2% metolazone). Interestingly, furosemide use was associated with a 70% reduced risk of adverse outcome (P ¼ .004).
Discussion Results Patients had a mean age of 66 15 (SD) years (30e101 years), 58% were female, with a mean length of hospital stay (LOS) of 12 11 (SD) days, 30% were NH residents, 58% had hyponatremia at admission, 37% were African American, 32% were Hispanic, 28% were White, and 3% were Asian. Death, mentation change, seizures, weakness, muscle cramps and seizures occurred in 7.0%, 8.7%, 1.6%, 41.8%, and 24.2% of the sample, respectively. Comparing these individual characteristics by residence showed that NH residents were significantly older (P < .00005) and had longer LOS (P ¼ .0153) than C residents but the female/male ratios (P ¼ .925) and racial distribution (P ¼ .562) were similar between both groups. Logistic regression modeling examined whether patient characteristics were factors related to (1) hyponatremia at admission or (2) risk factors for adverse outcome or death during hospitalization. Table 1 summarizes the results that examined for patient characteristics related to hyponatremia at admission. In this sample, the
Hyponatremia, defined as serum sodium levels <135 mEq/L, commonly results from dilution effects, with an increase in body water, and normal or increased body sodium. Hyponatremia less commonly results from sodium depletion, as from diarrhea or excessive diuretic use, where body water may also be depleted. Hyponatremia is common in hospitalized elderly and associated with increased morbidity and mortality.1,2 Signs and symptoms of hyponatremia depend on the magnitude and rapidity of decline in sodium levels. Manifestations include nausea, malaise, headache, lethargy, confusion, obtundation, stupor, seizures, and coma. As stated, correlations between severity of symptoms and degree of hyponatremia often are poor. Iatrogenic components are often contributory, including the increased administration of fluids either orally, intravenously, or via tube feeding5 and the use of medications that cause sodium excretion and water retention, such as thiazides,6 or stimulate ADH, such as antipsychotics, opioids, anticancer agents, and NSAIDs.
1525-8610/$ - see front matter Published by Elsevier Inc. on behalf of the American Medical Directors Association, Inc. doi:10.1016/j.jamda.2011.08.010
Letter to the Editor / JAMDA 13 (2012) e8ee9
Conclusion
Table 1 Risk Factors for Admission with Hyponatremia* Variable Na <135 mEq/L Age Residence African Americans Hispanics Gender Na <125 mEq/L Age Residence African Americans Hispanics Gender
Associated Risk
P-value
10% increased risk for each year increase in age (>30 years) NH residents 43 times more likely than C residents 11 times more likely than White or Asian patients 88% less likely than White or Asian patients Not related
<.0005 <.0005 .001
References Not related NH residents 16 times more likely than C residents Not related Not related Not related
NS .002 NS NS NS
Table 2 Risk of Adverse Outcome* during Hospitalization
Adverse outcome Age Residence Race Gender LOS Hyponatremiaz Decreasing Nax Death Age Residence Race Gender LOS Hyponatremiaz Decreasing Nax
Hospitalization of NH residents with hyponatremia is associated with poor outcome. Perhaps NH residents ought to be hospitalized only when clearly indicated and necessary, with steps taken to keep their hospital stay short. Finally, it is our responsibility to address polypharmacy and inappropriate medication use, factors contributing to iatrogenic adverse events (such as hyponatremia) in long term care.
.004 NSy
* Logistic regression analysis used and yNS refers to not significantly different; the Na <135 mEq/L regression had an overall P < .00005 and an R2 ¼ .3431 and the Na <125 mEg/L regression had an overall P ¼ .0100 and an R2 ¼ .1786.
Variable
e9
Associated Risk
P-value
Not related Not related Not related Males were 72% less likely than females Not related Not related 4.2-fold increased risk
NSy NS NS .009 NS NS .027
23% increased risk per 1-year increase in age Not related Not related Not related Not related Not related Not related
.048 NSy NS NS NS NS NS
The adverse outcome regression had an overall P < .0022 and an R2 ¼ .1597 and the risk of death overall regression had an overall P ¼ .0005 and an R2 ¼ .5965. * Logistic regression analysis used. y NS refers to not significantly different, zat admission and xduring hospitalization.
Medications are particularly relevant in the geriatric population who are subject to polypharmacy and use of over-the-counter drugs.7,8 In this small sample of hospitalized Bronx adults, we identified several independent risk factors for hyponatremia at admission. NH residents were 43-fold more likely to be hospitalized with hyponatremia (Na <135) and 16-fold more likely to be admitted with serum Na <125 mEq/L than were C patients. In addition, a declining serum Na during hospitalization increased the risk of adverse outcome 4-fold; an increasing patient age was a strong risk factor for death. Interestingly, loop diuretics appeared protective.
1. Upadhyay A, Jaber BL, Madias NE. Incidence and prevalence of hyponatremia. Am J Med 2006;119(7 Suppl 1):S30eS35. Review. 2. Upadhyay A, Jaber BL, Madias NE. Epidemiology of hyponatremia. Semin Nephrol 2009;29(3):227e238. 3. Crecilius C. Dehydration: Myth and reality. J Am Med Dir Assoc. 2008;9: 287e288. 4. Thomas DR, Cote TR, Levenson SA, et al. Understanding clinical dehydration and its treatment. J Am Med Dir Assoc. 2008;9:292e301. 5. Miller M, Morley JE, Rubenstein LZ. Hyponatremia in a nursing home population. J Am Geriatr Soc. 1995;43(12):1410e1413. 6. Rosholm JU, Nybo H, Andersen Ranberg K, et al. Hyponatremia in the very old non-hospitalized people. Drugs Aging 2002;19(9):685e693. 7. Allison SP, Lobo DN. Fluid and electrolytes in the elderly. Curr Opin Clin Nutr Metab Care 2004;7(1):27e33. 8. Passare G, Viitanen M, Törring O, et al. Sodium and potassium disturbances in the elderly: prevalence and association with drug use. Clin Drug Investig 2004; 24(9):535e544.
M. Choudhury, MD Resident in Medicine Montefiore Medical Center (North Div.) Bronx, NY K. Aparanji, MD Fellow in Geriatric Medicine Montefiore Medical Center (North Div.) Bronx, NY E.P. Norkus, PhD, FACN Director, Division of Medical Research Dept. of Medicine, Montefiore Medical Ctr. (North Div.) Bronx, NY Assoc. Professor, Community and Preventive Medicine New York Medical College Valhalla, NY E-mail address: enorkus@montefiore.org (E.P. Norkus) T.S. Dharmarajan, MD, FACP, AGSF Vice Chairman Dept. of Medicine Clinical Director, Geriatrics Director Geriatric Medicine Fellowship Program Montefiore Medical Ctr (North Div.), Bronx, NY Prof. of Medicine and Associate Dean New York Medical College Valhalla, NY E-mail address: [email protected] (T.S. Dharmarajan)
JAMDA journal homepage: www.jamda.com
Letter to the Editor
Hyponatremia in Hospitalized Nursing Home Residents and Outcome: Minimize Hospitalization and Keep the Stay Short! To the Editor: Hyponatremia, defined as serum sodium (Na) <135 mEq/L is a common electrolyte abnormality resulting from illness or medication use, and is associated with morbidity and mortality.1,2 The etiology of hyponatremia, the time taken to determine the etiology and the speed of correction may all contribute to outcome. Often, hyponatremia, a condition where body water can be normal, decreased or increased, is confused with disorders of clinical dehydration and its treatment.3,4 This pilot study examined whether the general characteristics of nursing home (NH) and community (C) patients, length of hospitalization (LOS), changes in serum Na ([ or Y) during hospitalization, existing comorbidity and manifestations might be risk factors for adverse outcome in hyponatremia. Since diuretics as a drug class clearly influence sodium and water metabolism, the impact of diuretics at admission or during hospitalization was also examined. Methods Data were collected during 2008, on 244 patients with hyponatremia or on diuretics at admission. Medical history, comorbidity, medications prescribed during hospitalization, manifestations, laboratory results and outcomes were recorded. For this analysis, adverse outcome was defined as any combination of (1) death, (2) alteration in mentation (drowsiness, stupor, coma), (3) seizures, (4) lethargy or weakness, and (5) muscle cramps.
risk of having a serum Na <135 mEq/L at admission increased by 10% for every 1-year increase in age (>30 years) (P < .0005) and, independently, by 43-fold in NH compared to C residents (P < .0005). Further, hyponatremia occurred significantly more often in African Americans (P ¼ .001) but less often in Hispanics (P ¼ .004) compared to White and Asian patients. Patient gender was found to be unrelated to hyponatremia at admission. A second analysis determined that the risk of having a serum Na <125 mEq/L at admission was 16-fold more likely in NH than community adults (P ¼ .002) but that age, gender, and race were not factors. Table 2 summarizes results of testing for risk factors for adverse outcome (defined above) or death during hospitalization. In this sample, the risk of adverse outcome was 72% less likely in males than females (P ¼ .009) but increased by 4.2-fold in patients with decreasing serum Na during hospitalization (P ¼ .027). Age, race, place of residence and LOS were determined not to be factors contributing to the risk of adverse outcome. A separate analysis that tested for risk factors for death during hospital stay determined a 23% increased risk of death for every 1-year increase in age (>30 years) (P ¼ .048) but that sex, place of residence (NH versus C), race, hyponatremia at admission, decreasing Na during hospitalization and LOS were unrelated. Diuretics were used by 28% of patients in the sample (12% thiazides, 14% furosemide, 2% metolazone). Interestingly, furosemide use was associated with a 70% reduced risk of adverse outcome (P ¼ .004).
Discussion Results Patients had a mean age of 66 15 (SD) years (30e101 years), 58% were female, with a mean length of hospital stay (LOS) of 12 11 (SD) days, 30% were NH residents, 58% had hyponatremia at admission, 37% were African American, 32% were Hispanic, 28% were White, and 3% were Asian. Death, mentation change, seizures, weakness, muscle cramps and seizures occurred in 7.0%, 8.7%, 1.6%, 41.8%, and 24.2% of the sample, respectively. Comparing these individual characteristics by residence showed that NH residents were significantly older (P < .00005) and had longer LOS (P ¼ .0153) than C residents but the female/male ratios (P ¼ .925) and racial distribution (P ¼ .562) were similar between both groups. Logistic regression modeling examined whether patient characteristics were factors related to (1) hyponatremia at admission or (2) risk factors for adverse outcome or death during hospitalization. Table 1 summarizes the results that examined for patient characteristics related to hyponatremia at admission. In this sample, the
Hyponatremia, defined as serum sodium levels <135 mEq/L, commonly results from dilution effects, with an increase in body water, and normal or increased body sodium. Hyponatremia less commonly results from sodium depletion, as from diarrhea or excessive diuretic use, where body water may also be depleted. Hyponatremia is common in hospitalized elderly and associated with increased morbidity and mortality.1,2 Signs and symptoms of hyponatremia depend on the magnitude and rapidity of decline in sodium levels. Manifestations include nausea, malaise, headache, lethargy, confusion, obtundation, stupor, seizures, and coma. As stated, correlations between severity of symptoms and degree of hyponatremia often are poor. Iatrogenic components are often contributory, including the increased administration of fluids either orally, intravenously, or via tube feeding5 and the use of medications that cause sodium excretion and water retention, such as thiazides,6 or stimulate ADH, such as antipsychotics, opioids, anticancer agents, and NSAIDs.
1525-8610/$ - see front matter Published by Elsevier Inc. on behalf of the American Medical Directors Association, Inc. doi:10.1016/j.jamda.2011.08.010
Letter to the Editor / JAMDA 13 (2012) e8ee9
Conclusion
Table 1 Risk Factors for Admission with Hyponatremia* Variable Na <135 mEq/L Age Residence African Americans Hispanics Gender Na <125 mEq/L Age Residence African Americans Hispanics Gender
Associated Risk
P-value
10% increased risk for each year increase in age (>30 years) NH residents 43 times more likely than C residents 11 times more likely than White or Asian patients 88% less likely than White or Asian patients Not related
<.0005 <.0005 .001
References Not related NH residents 16 times more likely than C residents Not related Not related Not related
NS .002 NS NS NS
Table 2 Risk of Adverse Outcome* during Hospitalization
Adverse outcome Age Residence Race Gender LOS Hyponatremiaz Decreasing Nax Death Age Residence Race Gender LOS Hyponatremiaz Decreasing Nax
Hospitalization of NH residents with hyponatremia is associated with poor outcome. Perhaps NH residents ought to be hospitalized only when clearly indicated and necessary, with steps taken to keep their hospital stay short. Finally, it is our responsibility to address polypharmacy and inappropriate medication use, factors contributing to iatrogenic adverse events (such as hyponatremia) in long term care.
.004 NSy
* Logistic regression analysis used and yNS refers to not significantly different; the Na <135 mEq/L regression had an overall P < .00005 and an R2 ¼ .3431 and the Na <125 mEg/L regression had an overall P ¼ .0100 and an R2 ¼ .1786.
Variable
e9
Associated Risk
P-value
Not related Not related Not related Males were 72% less likely than females Not related Not related 4.2-fold increased risk
NSy NS NS .009 NS NS .027
23% increased risk per 1-year increase in age Not related Not related Not related Not related Not related Not related
.048 NSy NS NS NS NS NS
The adverse outcome regression had an overall P < .0022 and an R2 ¼ .1597 and the risk of death overall regression had an overall P ¼ .0005 and an R2 ¼ .5965. * Logistic regression analysis used. y NS refers to not significantly different, zat admission and xduring hospitalization.
Medications are particularly relevant in the geriatric population who are subject to polypharmacy and use of over-the-counter drugs.7,8 In this small sample of hospitalized Bronx adults, we identified several independent risk factors for hyponatremia at admission. NH residents were 43-fold more likely to be hospitalized with hyponatremia (Na <135) and 16-fold more likely to be admitted with serum Na <125 mEq/L than were C patients. In addition, a declining serum Na during hospitalization increased the risk of adverse outcome 4-fold; an increasing patient age was a strong risk factor for death. Interestingly, loop diuretics appeared protective.
1. Upadhyay A, Jaber BL, Madias NE. Incidence and prevalence of hyponatremia. Am J Med 2006;119(7 Suppl 1):S30eS35. Review. 2. Upadhyay A, Jaber BL, Madias NE. Epidemiology of hyponatremia. Semin Nephrol 2009;29(3):227e238. 3. Crecilius C. Dehydration: Myth and reality. J Am Med Dir Assoc. 2008;9: 287e288. 4. Thomas DR, Cote TR, Levenson SA, et al. Understanding clinical dehydration and its treatment. J Am Med Dir Assoc. 2008;9:292e301. 5. Miller M, Morley JE, Rubenstein LZ. Hyponatremia in a nursing home population. J Am Geriatr Soc. 1995;43(12):1410e1413. 6. Rosholm JU, Nybo H, Andersen Ranberg K, et al. Hyponatremia in the very old non-hospitalized people. Drugs Aging 2002;19(9):685e693. 7. Allison SP, Lobo DN. Fluid and electrolytes in the elderly. Curr Opin Clin Nutr Metab Care 2004;7(1):27e33. 8. Passare G, Viitanen M, Törring O, et al. Sodium and potassium disturbances in the elderly: prevalence and association with drug use. Clin Drug Investig 2004; 24(9):535e544.
M. Choudhury, MD Resident in Medicine Montefiore Medical Center (North Div.) Bronx, NY K. Aparanji, MD Fellow in Geriatric Medicine Montefiore Medical Center (North Div.) Bronx, NY E.P. Norkus, PhD, FACN Director, Division of Medical Research Dept. of Medicine, Montefiore Medical Ctr. (North Div.) Bronx, NY Assoc. Professor, Community and Preventive Medicine New York Medical College Valhalla, NY E-mail address: enorkus@montefiore.org (E.P. Norkus) T.S. Dharmarajan, MD, FACP, AGSF Vice Chairman Dept. of Medicine Clinical Director, Geriatrics Director Geriatric Medicine Fellowship Program Montefiore Medical Ctr (North Div.), Bronx, NY Prof. of Medicine and Associate Dean New York Medical College Valhalla, NY E-mail address: [email protected] (T.S. Dharmarajan)