title: Second-Generation Antidepressants and Hyponatremia Risk: A Population-Based Cohort Study of Older Adults.
abstract: BACKGROUND
  Hyponatremia may occur after initiation of a second-generation antidepressant drug. However, the magnitude of this risk among older adults in routine care is not well characterized.
  
  
  METHODS
  Retrospective, population-based, matched-cohort study.
  
  
  METHODS
  In Ontario, Canada, 2003 to 2012, we compared older adults with a mood or anxiety disorder who were dispensed 1 of 9 second-generation antidepressant drugs with matched adults with comparable indicators of baseline health who were not dispensed an antidepressant drug (n=138,246 per group). A similar comparison was made in a subpopulation with available laboratory data (n=4,186 per group).
  
  
  METHODS
  Second-generation antidepressant prescription versus no antidepressant prescription.
  
  
  RESULTS
  The primary outcome was hospitalization with hyponatremia. A secondary outcome was hospitalization with both hyponatremia and delirium.
  
  
  METHODS
  We assessed hospitalization with hyponatremia using a diagnosis code and, in the subpopulation, serum sodium values. We assessed hospitalization with hyponatremia and delirium using a combination of diagnosis codes.
  
  
  RESULTS
  Second-generation antidepressant use versus nonuse was associated with higher 30-day risk for hospitalization with hyponatremia (450/138,246 [0.33%] vs 84/138,246 [0.06%]; relative risk [RR], 5.46 [95% CI, 4.32-6.91]). This association was consistent in the subpopulation with serum sodium values (73/4,186 [1.74%] vs 18/4,186 [0.43%]; RR, 4.23 [95% CI, 2.50-7.19]; absolute risk increase, 1.31% [95% CI, 0.87%-1.75%]). Second-generation antidepressant use versus nonuse was also associated with higher 30-day risk for hospitalization with both hyponatremia and delirium (28/138,246 [0.02%] vs 7/138,246 [0.005%]; RR, 4.00 [95% CI, 1.75-9.16]).
  
  
  CONCLUSIONS
  Measures of serum sodium could be ascertained in only a subpopulation.
  
  
  CONCLUSIONS
  Use of a second-generation antidepressant in routine care by older adults is associated with an approximate 5-fold increase in 30-day risk for hospitalization with hyponatremia compared to nonuse. However, the absolute increase in 30-day incidence is low.
authors: Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada; Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada.
authors: Sonja
authors: S
authors: Gandhi
authors: Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada; Institute for Clinical Evaluative Sciences, London, Ontario, Canada.
authors: Salimah Z
authors: SZ
authors: Shariff
authors: Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada; Institute for Clinical Evaluative Sciences, London, Ontario, Canada.
authors: Ahmed
authors: A
authors: Al-Jaishi
authors: Department of Psychiatry, Western University, London, Ontario, Canada.
authors: Jeffrey P
authors: JP
authors: Reiss
authors: Institute for Clinical Evaluative Sciences, London, Ontario, Canada; Keenan Research Centre in the Li Ka Shing Knowledge Institute of St Michael's Hospital, Toronto, Ontario, Canada.
authors: Muhammad M
authors: MM
authors: Mamdani
authors: Institute for Clinical Evaluative Sciences, London, Ontario, Canada; Division of Clinical Pharmacology, Department of Medicine, Western University, London, Ontario, Canada.
authors: Daniel G
authors: DG
authors: Hackam
authors: Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada; Institute for Clinical Evaluative Sciences, London, Ontario, Canada.
authors: Lihua
authors: L
authors: Li
authors: Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada; Institute for Clinical Evaluative Sciences, London, Ontario, Canada.
authors: Eric
authors: E
authors: McArthur
authors: Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada; Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada.
authors: Matthew A
authors: MA
authors: Weir
authors: Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada; Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada; Institute for Clinical Evaluative Sciences, London, Ontario, Canada. Electronic address: amit.garg@lhsc.on.ca.
authors: Amit X
authors: AX
authors: Garg
mesh_terms: D000368:Aged; D018687:Antidepressive Agents, Second-Generation / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007010:Hyponatremia / Q000139:chemically induced* / Q000453:epidemiology; D008297:Male; D012189:Retrospective Studies; D018570:Risk Assessment; D013997:Time Factors
chemical_list: D018687:Antidepressive Agents, Second-Generation
keywords: Hyponatremia; antidepressants; anxiety disorder; citalopram; duloxetine; electrolyte disorder; escitalopram; fluoxetine; fluvoxamine; mirtazapine; mood disorder; older adults; paroxetine; second-generation antidepressant; sertraline; serum sodium; syndrome of inappropriate antidiuretic hormone secretion (SIADH); venlafaxine