Mortality among Patients Admitted to Hospitals on Weekends as Compared with Weekdays

BACKGROUND: The level of staffing in hospitals is often lower on weekends than on weekdays, despite a presumably consistent day-to-day burden of disease. It is uncertain whether in-hospital mortality rates among patients with serious conditions differ according to whether they are admitted on a weekend or on a weekday. METHODS: We analyzed all acute care admissions from emergency departments in Ontario, Canada, between 1988 and 1997 (a total of 3,789,917 admissions). We compared in-hospital mortality among patients admitted on a weekend with that among patients admitted on a weekday for three prespecified diseases: ruptured abdominal aortic aneurysm (5454 admissions), acute epiglottitis (1139), and pulmonary embolism (11,686) and for three control diseases: myocardial infarction (160,220), intracerebral hemorrhage (10,987), and acute hip fracture (59,670), as well as for the 100 conditions that were the most common causes of death (accounting for 1,820,885 admissions). RESULTS: Weekend admissions were associated with significantly higher in-hospital mortality rates than were weekday admissions among patients with ruptured abdominal aortic aneurysms (42 percent vs. 36 percent, P<0.001), acute epiglottitis (1.7 percent vs. 0.3 percent, P=0.04), and pulmonary embolism (13 percent vs. 11 percent, P=0.009). The differences in mortality persisted for all three diagnoses after adjustment for age, sex, and coexisting disorders. There were no significant differences in mortality between weekday and weekend admissions for the three control diagnoses. Weekend admissions were also associated with significantly higher mortality rates for 23 of the 100 leading causes of death and were not associated with significantly lower mortality rates for any of these conditions. CONCLUSIONS: Patients with some serious medical conditions are more likely to die in the hospital if they are admitted on a weekend than if they are admitted on a weekday.