Background Reperfusion times for ischemic stroke occurring in the outpatient setting have improved significantly in recent years. However, quality improvement efforts have largely ignored ischemic stroke occurring in patients hospitalized for unrelated indications.

Methods We performed a cohort study involving patients with ischemic stroke (with inpatient or outpatient onset) from 2009 to 2013 who were registered in the Statewide Planning and Research Cooperative System (SPARCS) database. A propensity score-adjusted regression analysis was used to assess the association of location of onset and outcomes. Mixed effects methods were employed to control for clustering at the hospital level.

Results Of the 176 571 ischemic strokes, 160 157 (90.7%) occurred outside of a hospital and 16 414 (9.3%) occurred in patients hospitalized for unrelated indications. Using a logistic regression model with propensity score adjustment, we demonstrated that inpatient stroke onset was associated with increased inpatient mortality (OR 3.09; 95% CI 2.81 to 3.38), rate of discharge to rehabilitation (OR 2.57; 95% CI 2.37 to 2.79), and length of stay (LOS) (β=11.58; 95% CI 10.73 to 12.42). In addition, it was associated with lower odds (OR 0.69; 95% CI 0.62 to 0.77) of undergoing stroke-related interventions (mechanical thrombectomy and intravenous tissue plasminogen activator) compared with outpatient stroke onset.

Conclusions Using a comprehensive all-payer cohort of patients with ischemic stroke in New York State, we identified an association of inpatient stroke onset with fewer stroke-related interventions and increased mortality, rate of discharge to rehabilitation, and LOS.