Effect of Weekend Admission on In-Hospital Mortality in Patients with Ischemic Stroke: An Analysis of Korean Nationwide Claims Data from 2002 to 2013

Background Studies conducted on patients with stroke in countries other than Korea demonstrated a phenomenon known as the weekend effect on 7-day, 30-day, and in-hospital mortalities. We studied patients with stroke using nationwide cohort data to determine if there was a weekend effect on mortality in a Korean population. Methods Nationwide cohort data, collected from 2002 to 2013, were searched for all hospitalizations via the emergency department due to ischemic stroke. Cox's proportional hazards frailty model was employed, and we adjusted for all patient and hospital characteristics. Results There were 8957 patients with ischemic stroke admitted via the emergency department: 2632 weekend admissions and 6325 weekday admissions. Of these, 478 (5.3%) patients were dead. After adjusting for patient and hospital characteristics, the frailty model analysis revealed significantly higher in-hospital mortality in patients admitted on weekends than in those admitted on weekdays (hazard ratio [HR], 1.22; 95% confidence interval [CI], 1.01-1.47). We obtained consistent results for the 30-day mortality findings (HR, 1.27; 95% CI, 1.04-1.55). However, no significant differences were observed in the 7-day mortality (HR, 1.13; 95% CI,.88-1.45). Conclusions Weekend admission for ischemic stroke was significantly associated with higher in-hospital and 30-day mortality after adjusting for individual characteristics and hospital factors.