Methods: A retrospective analysis of all medical and pharmacy claims of Medicaid stroke patients (ICD-9 Codes 430-438) for the period of 1/1/01-12/31/03 was performed. Inclusion: at least one month of follow up. Exclusion (to obtain incident cohort): stroke diagnosis between 1/1-6/30/01. Outcome measure: non-recurrence of stroke. Using Cox proportional hazard models, we compare non-recurrence rates of combined therapies of aspirin with clopidogrel versus aspirin alone, and warfarin with aspirin or clopidogrel versus warfarin alone; while adjusting for age, gender, race, urban residence, heart disease, hypertension, diabetes, blood pressure or lipid lowering drugs and persistence on the first stroke preventive drug taken post-stroke.

Results: Total of 925 patients, 36% older than 60, 58% African American, and 35% males. About 70% of those who started on aspirin and added clopidogrel had a recurrence and 66% of those who started on warfarin and added either clopidogrel or aspirin had a recurrence. Patients who start on aspirin and add clopidogrel versus aspirin alone (HR= 2.43, p<0.001, CI 1.59-3.73) and those who start on warfarin and add aspirin or clopidogrel versus warfarin alone (HR=1.68, p=0.02, CI 1.08-2.62) are more likely not to have a recurrence. Patients who start on aspirin and add clopidogrel and have hypertension post-stroke (HR=0.63, p=0.05, CI 0.40-0.99) are less likely to avoid a recurrence. The same is true for patients who start on warfarin and add aspirin or clopidogrel (HR=0.60, p=0.01, CI 0.41-0.88).

Conclusion: Combination therapies of aspirin with clopidogrel, and warfarin with aspirin or clopidogrel decrease the risk of recurrent stroke, when compared to monotherapies of aspirin or warfarin alone. Healthcare plans may consider those therapies in managing patients with stroke.