Weekend versus Weekday Admission and In-Hospital Mortality from Ischemic Stroke in Japan

Background: The initial treatment of acute ischemic stroke critically affects patient outcome. Patient outcome may also be associated with the day of hospital admission due to differences in the number of the hospital staff between weekdays and weekends. We aimed to assess the effect of weekend admission on in-hospital mortality among patients with ischemic stroke in Japan. Methods: We analyzed patients with ischemic stroke from a large nationwide administrative dataset. The patients were grouped according to the treatment ward to which they were initially admitted: a general medical ward (GMW) or an intensive or stroke care unit (S-ICU). The primary outcome, in-hospital mortality, was compared between the patients admitted on a weekday versus weekend according to the initial treatment ward. A generalized estimated equation was applied for multivariate analysis. Results: In total, 47,885 patients were included in the study. Of these patients, 32.0% were admitted to an S-ICU and 27.8% were admitted to a GMW on a weekend. The estimated in-hospital mortality rate was significantly higher among the patients admitted to a GMW on a weekend compared with those admitted on a weekday (7.9% versus 7.0%), but this difference was not significant after adjusting for the patients' background characteristics. The estimated in-hospital mortality rates of the patients admitted to an S-ICU were similar between weekend and weekday admissions (10.0% versus 9.9%). Conclusions: No significant effect of weekend admission in-hospital mortality was observed in our study population regardless of the initial treatment ward.