title: Recurrent hospitalizations with moderate to severe hyponatremia in older adults and its associated mortality.
abstract: BACKGROUND
  Recurrent hospitalizations with hyponatremia are commonly encountered in older adults admitted to Internal Medicine wards. However, the incidence and the prognostic implication of this phenomenon have never been studied.
  
  
  METHODS
  Medical charts of all older adults (≥75 years) admitted to Internal Medicine wards at a tertiary medical center during 2009-2010 with symptomatic moderate to severe hyponatremia (blood sodium ≤130 meq/l) upon admission were reviewed. The study group included patients with one or more hospitalizations with hyponatremia in the year following the first hospitalization with hyponatremia. The control group included patients with a single hospitalization with hyponatremia. Mortality rates were studied one year following the second hospitalization with hyponatremia in the study group and one year following the single hospitalization with hyponatremia in the control group. Regression analysis was used to study the association between recurrent hospitalizations with hyponatremia and 1-year mortality while controlling for demographics, chronic co-morbidities, albumin serum levels, and the number of hospitalizations.
  
  
  RESULTS
  The cohort included 431 older adults: 301 (69.8%) women; mean age of 84.6±5.6 years. Overall, 120 (27.8%) patients had recurrent hospitalizations with hyponatremia and 125 (29.0%) patients died within a year. 1-Year mortality rates were higher in patients with recurrent hospitalizations with hyponatremia than in patients with a single hospitalization with hyponatremia (42.5% vs. 23.8%; p<0.0001). Regression analysis showed that recurrent hospitalizations with hyponatremia were independently associated with 1-year mortality (odds ratio 1.9; 95% confidence interval 1.1-3.2; p=0.018).
  
  
  CONCLUSIONS
  Recurrent hospitalizations with hyponatremia in older adults are common and associated with 1-year mortality.
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Israel.
authors.forename: Sheizaf
authors.initials: S
authors.lastname: Gefen
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Israel; Department of Hematology, Sourasky Medical Center, Tel-Aviv, Israel.
authors.forename: Erel
authors.initials: E
authors.lastname: Joffe
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Israel; Department of Internal Medicine E, Sheba Medical Center, Tel-Hashomer, Israel.
authors.forename: Haim
authors.initials: H
authors.lastname: Mayan
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Israel; Department of Geriatrics and Internal Medicine D, Sheba Medical Center, Tel-Hashomer, Israel. Electronic address: danj@post.tau.ac.il.
authors.forename: Dan
authors.initials: D
authors.lastname: Justo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007010:Hyponatremia / Q000453:epidemiology* / Q000628:therapy; D015994:Incidence; D007557:Israel / Q000453:epidemiology; D008297:Male; D010359:Patient Readmission / Q000639:trends*; D011446:Prospective Studies; D012008:Recurrence; D012720:Severity of Illness Index; D015996:Survival Rate / Q000639:trends
keywords: Mortality; Older adults; Recurrent hyponatremia