Post‐Discharge Antiseizure Medication Use and Poststroke Survival: An Emulated Target Trial in Older Adults
Madhav Sankaranarayanan, Maria A. Donahue, Julianne D. Brooks, Shuo Sun, Joseph P. Newhouse, Deborah Blacker, Sebastien Haneuse, Sonia Hernández Díaz, Lidia M. V. R. MouraABSTRACT
Purpose
Levetiracetam is commonly prescribed for seizure prophylaxis after acute ischemic stroke (AIS) and often continued beyond discharge. While its short‐term effectiveness for preventing poststroke seizures is established, it is unclear whether prolonged use improves survival, particularly in older adults. We estimated the effect of continued levetiracetam use on 90‐day mortality among Medicare beneficiaries after AIS.
Methods
Using Traditional Medicare claims data (2008–2021), we identified beneficiaries aged ≥ 65 years hospitalized for AIS who initiated outpatient levetiracetam within 90 days of discharge. After 1 month of continued poststroke levetiracetam use (start of follow‐up), we compared 90‐day mortality between patients with a new levetiracetam dispensation within a 14‐day grace period post‐follow‐up and those without one. We performed cloning, censoring, and weighting to address immortal‐time bias and estimated standardized mortality risks, risk differences, and 95% confidence intervals (CIs).
Results
Among 3212 eligible beneficiaries, 1779 (55.4%) received a new levetiracetam dispensation within the 14‐day grace period. After adjustment for demographics, hospitalization characteristics, timing of initiation, and comorbidities, continued use was associated with lower 90‐day mortality than discontinuation (53 vs. 62 deaths per 1000; risk difference −9 per 1000; 95% CI: −12, −5).
Conclusion
Among older Medicare beneficiaries who initiated levetiracetam after AIS, continued outpatient use was associated with lower short‐term 90‐day mortality, particularly among patients aged ≥ 75 years. These findings should not be interpreted as support for routine or indefinite continuation, because the claims‐based design cannot assess seizure recurrence, functional outcomes, quality of life, treatment indication, or potential neuropsychiatric harms.