Comparative risk of major health events among individuals prescribed different antiseizure medications following ischemic stroke.

Abstract

Objective: The aim of this study was to compare the risk of seizure, recurrent stroke, fall or fracture, and mortality in individuals prescribed different antiseizure medications (ASMs) following an ischemic stroke.

Methods: We identified all patients admitted to a Victorian public or private hospital with a principal diagnosis of an incident ischemic stroke between 2013 and 2017 and dispensed an ASM within 12 months of discharge. Cox proportional hazards regression was used to estimate the risk of cause-specific rehospitalization or emergency department visits (seizure, fall or fracture, recurrent stroke) and all-cause mortality over a 2-year period. Inverse probability of treatment weighting was applied to each model to adjust for baseline covariates.

Results: Of 19 601 individuals hospitalized for incident ischemic stroke, 897 initiated ASM treatment within 12 months. More than three quarters were initiated on a non-enzyme-inducing ASM (78.0%). Levetiracetam (41.9%), valproate (28.4%), and carbamazepine (11.4%) were commonly dispensed initial ASMs. Non-enzyme-inducing ASMs demonstrated similar risk of seizure (hazard ratio [HR] = .93, 95% confidence interval [CI] = .63-1.37), fall or fracture (HR = 1.47, 95% CI = .92-2.34), stroke (HR = .83; 95% CI = .52-1.33), and mortality (HR = .96; 95% CI = .69-1.32) compared to enzyme-inducing ASMs. However, when valproate was grouped as a separate class, non-enzyme-inducing ASMs (HR = 1.67, 95% CI = 1.04-2.71) showed higher risk of fall or fracture compared to enzyme-inducing ASMs.

Significance: At a population level, ASMs of different types showed no significant differences in the risk of hospitalization or emergency department presentation for seizure, fall or fracture, stroke, and mortality within 2 years of an incident stroke presentation, suggesting similar short-term health outcomes in a real-world setting. Future research should investigate decision-making around ASM choice for stroke survivors and examine the impact of long-term ASM exposure on health outcomes.