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Antiepileptic drugs and hyponatremia in older adults: Two population‐based cohort studies
Author(s) -
Gandhi Sonja,
McArthur Eric,
Mamdani Muhammad M.,
Hackam Daniel G.,
McLachlan Richard S.,
Weir Matthew A.,
Burneo Jorge G.,
Garg Amit X.
Publication year - 2016
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/epi.13593
Subject(s) - medicine , hyponatremia , carbamazepine , retrospective cohort study , topiramate , population , cohort study , propensity score matching , relative risk , pediatrics , confidence interval , cohort , epilepsy , psychiatry , environmental health
Summary Objective To examine the 30‐day risk of hospitalization with hyponatremia associated with carbamazepine, valproic acid (V), phenytoin (P), or topiramate (T) use compared to nonuse in the outpatient setting among older adults. Methods We conducted two population‐based, retrospective cohort studies in Ontario, Canada, between 2003 and 2015 using administrative health care databases of older adults. The first study compared carbamazepine users to a propensity‐score matched group of antiepileptic drug nonusers, whereas the second compared V‐P‐T users to a propensity‐score matched group of antiepileptic nonusers. The primary outcome was hospitalization with hyponatremia within 30 days of an antiepileptic prescription. Results The baseline characteristics between matched groups were similar in both cohorts. Carbamazepine use versus nonuse was associated with a higher 30‐day risk of hospitalization with hyponatremia (82/21,191 [0.39%] versus 30/63,573 [0.05%]; relative risk [RR] 8.20, 95% confidence interval [CI] 5.40–12.46). Similarly, V‐P‐T use versus nonuse was associated with a higher 30‐day risk of hospitalization with hyponatremia (34/20,155 [0.17%] versus 26/40,310 [0.06%]; RR 2.62, 95% CI 1.57–4.36). Significance Older adults prescribed carbamazepine and V‐P‐T have a higher risk of being hospitalized with hyponatremia compared to other adults with similar indicators of baseline health who were not prescribed antiepileptic drugs. Physicians should be mindful of this risk; when a patient presents to a hospital with symptomatic hyponatremia these drugs should be considered as potential causes.