ObjectiveIt is uncertain whether patients with cardioembolic stroke and without a guidance-based indication for statin therapy should be administered a statin for prevention of subsequent vascular events. This study was performed to determine whether the statin therapy is beneficial in preventing major vascular events in this population.MethodsUsing a prospective multicenter stroke registry database, we identified patients with acute cardioembolic stroke who were hospitalized between 2008 and 2015. Patients who had other established indications for statin therapy according to current guidelines were excluded. Major vascular event was defined as a composite of stroke recurrence, myocardial infarction, and vascular death. We performed frailty model analysis with the robust sandwich variance estimator using the stabilized inverse probability of treatment weighting method to estimate hazard ratios of statin therapy on outcomes.ResultsOf 6,124 patients with cardioembolic stroke, 2,888 (male 44.6%, mean age 75.3 years, 95% confidence interval [CI] 74.8–75.8) were eligible, and 1,863 (64.5%) were on statin therapy during hospitalization. After a median follow-up of 359 days, cumulative incidences of major vascular events were 9.3% in the statin users and 20.5% in the nonusers (p < 0.001 by log-rank test). The adjusted hazard ratios of statin therapy were 0.39 (95% CI 0.31–0.48) for major vascular events, 0.81 (95% CI 0.57–1.16) for stroke recurrence, 0.28 (95% CI 0.21–0.36) for vascular death, and 0.53 (95% CI 0.45–0.61) for all-cause death.ConclusionStarting statin during the acute stage of ischemic stroke may reduce the risk of major vascular events, vascular death, and all-cause death in patients with cardioembolic stroke with no guidance-based indication for statin.