The weekend effect revisited: evidence from the Upper Austrian stroke registry.

Empirical evidence on the so-called 'weekend-effect' on stroke mortality is mixed with some studies reporting significantly higher mortality for weekend admissions and others finding no difference. The aim of this paper is to enhance the evidence on the weekend-effect on stroke mortality using a rich stroke registry data set from Upper Austria and to discuss underlying reasons for the heterogeneity in results. Using logistic regressions and ordinary least squares regressions with hospital and year-fixed effects, the outcomes of weekend versus weekday admissions are compared for patients admitted to 16 hospitals in Upper Austria with transient ischemic attack (TIA), cerebral infarction or hemorrhage between 2007 and 2015. The primary outcomes include in-hospital mortality, 30-day and 90-day all-cause mortality as well as the length of hospital stay. In addition, we analyze differences in process-quality indicators between weekdays and weekends. Our results show that on weekends there are on average 25% fewer admissions than on weekdays with significantly higher in-hospital mortality. Adjusting for case-mix, the association between weekend admissions and mortality becomes null suggesting that the higher mortality on weekends is explained by heterogeneities in admissions rather than health-care quality.