One-Year Incidence, Time Trends, and Predictors of Recurrent Ischemic Stroke in Sweden From 1998 to 2010: An Observational Study.

BACKGROUND AND PURPOSE Recent data on the incidence, time trends, and predictors of recurrent ischemic stroke are limited for unselected patient populations. METHODS Data for ischemic stroke patients were obtained from The Swedish Stroke Register (Riksstroke) between 1998 and 2009 and merged with The Swedish National Inpatient Register. A reference group of patients was created by Statistics Sweden. The ischemic stroke patient cohort was divided into 4 time periods. Recurrent ischemic stroke within 1 year was recorded until 2010. Kaplan-Meier and Cox regression analyses were performed to study time trends and predictors of ischemic stroke recurrence. RESULTS Of 196 765 patients with ischemic stroke, 11.3% had a recurrent ischemic stroke within 1 year. The Kaplan-Meier estimates of the 1-year cumulative incidence of recurrent ischemic stroke decreased from 15.0% in 1998 to 2001 to 12.0% in 2007 to 2010 in the stroke patient cohort while the cumulative incidence of ischemic stroke decreased from 0.7% to 0.4% in the reference population. Age >75 years, prior ischemic stroke or myocardial infarction, atrial fibrillation without warfarin treatment, diabetes mellitus, and treatment with β-blockers or diuretics were associated with a higher risk while warfarin treatment for atrial fibrillation, lipid-lowering medication, and antithrombotic treatment (acetylsalicylic acid, dipyridamole) were associated with a reduced risk of recurrent ischemic stroke. CONCLUSIONS The risk of recurrent ischemic stroke decreased from 1998 to 2010. Well-known risk factors for stroke were associated with a higher risk of ischemic stroke recurrence; whereas, secondary preventive medication was associated with a reduced risk, emphasizing the importance of secondary preventive treatment.