title: Hyponatraemia in older medical patients: implications for falls and adverse outcomes of hospitalisation.
abstract: BACKGROUND
  Recent evidence suggests an association between hyponatraemia and falls.
  
  
  OBJECTIVE
  To determine the association of hyponatraemia with admission-associated falls (i.e. falls as part of the presenting complaint or during admission) and predefined adverse outcomes of hospitalisation.
  
  
  METHODS
  A case-control study of patients aged ≥65 years admitted with hyponatraemia during a 6-month period was conducted. The relevant data were collected by review of medical records and analysed in univariate and multivariate models.
  
  
  RESULTS
  The prevalence of hyponatraemia was 22% and more likely to be associated with the admission diagnoses of cardiovascular (P = 0.04) and metabolic disorders (P < 0.001), use of diuretics (P = 0.037) and a higher Charlson comorbidity score (P = 0.035). Hyponatraemia was independently associated with admission-associated falls (odds ratio (OR) 3.12, confidence interval (CI) 1.84-4.38, P < 0.001). The increased odds of falling were similar for mild (OR 3.15, CI 1.75-5.66) vs moderate to severe hyponatraemia (OR 3.07, CI 1.57-6.03). Although hyponatraemia had a significant independent association with increased length of stay (LOS) (OR 1.48, CI 1.22-1.79, P < 0.001) and change in residential care status to a more dependent category at discharge (OR 4.28, CI 1.68-10.859, P = 0.002), it was not associated with mortality or time to first unplanned readmission. Hyponatraemia was significantly associated with the need for inpatient rehabilitation; however, this was no longer significant when adjusted for falls.
  
  
  CONCLUSIONS
  Hyponatraemia is independently associated with increased risk of admission-associated falls. The degree of falls risk is similar regardless of the severity of hyponatraemia. Hyponatraemia is also an important determinant of many adverse outcomes of hospitalisation.
authors.affiliation: General Medicine Unit, Western Health, Melbourne, Victoria, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Ahamed
authors.forename: M
authors.initials: M
authors.lastname: Anpalahan
authors.forename: S
authors.initials: S
authors.lastname: Savvas
authors.forename: S
authors.initials: S
authors.lastname: Gibson
authors.forename: J
authors.initials: J
authors.lastname: Torres
authors.forename: E
authors.initials: E
authors.lastname: Janus
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000150:complications* / Q000453:epidemiology / Q000378:metabolism; D016022:Case-Control Studies; D015897:Comorbidity; D004232:Diuretics / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007010:Hyponatremia / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008659:Metabolic Diseases / Q000150:complications* / Q000453:epidemiology / Q000378:metabolism; D016017:Odds Ratio; D015995:Prevalence; D012307:Risk Factors
chemical_list: D004232:Diuretics
keywords: adverse outcome; elderly; fall; hospitalisation; hyponatraemia