Five-Year Rehospitalization Outcomes in a Cohort of Patients With Acute Ischemic Stroke: Medicare Linkage Study

Background and Purpose— The purposes of this study were to track mortality and rehospitalizations over 5 years poststroke in a stroke cohort (SC) and compare long-term risks of complications to a matched nonstroke cohort (NSC). Methods— A cohort design with a matched NSC comparison was used. The SC constituted a validated database of acute ischemic stroke patients, ≥65 years, hospitalized across 19 Minnesota hospitals in the year 2000. The NSC was constructed from the year 2000 General Medicare Population by matching SC members on age, race, and sex. Both cohorts were tracked across 5 years of Medicare claims data to identify dates and causes of rehospitalization and death dates. Kaplan–Meier survival curves estimated cumulative incidence rates. Cox models calculated adjusted hazard ratios. Results— Event rates and adjusted hazard ratios were: mortality: 1 year SC=24%, NSC=4%; 5 years SC=49%, NSC=24% (hazard ratio, 4.4; 95% CI, 3.6 to 5.5). Overall rehospitalization rates were: 1 year SC=49%, NSC=20%; 5 years SC=83%; NSC=63% (hazard ratio, 2.6; 95% CI, 2.2 to 3.0). Cause-specific 5-year rehospitalization rates were significantly higher in SC versus NSC for recurrent ischemic stroke, heart failure, cardiac events, any vascular events, pneumonia, and hip fractures. The excess risk of mortality and rehospitalizations in the SC persisted beyond the initial aftermath of the acute stroke (ie, beyond 30 days poststroke) and persisted even after 1 year poststroke. Average acute care Medicare charges in SC were more than doubled those in NSC. Conclusions— The high rates of acute care poststroke readmissions indicate a need for trials to prevent long-term complications in stroke survivors.