Effects of Weekend Admission and Hospital Teaching Status on In-hospital Mortality

Purpose: The effect of reduced hospital staffing during weekends on in-hospital mortality is not known. We compared mortality rates between patients admitted on weekends and weekdays and whether weekend-weekday variation in rates differed between patients admitted to teaching and nonteaching hospitals in California.

Methods: The sample comprised patients admitted to hospitals from the emergency department with any of 50 common diagnoses (N = 641,860). Mortality between patients admitted on weekends and those admitted on weekdays (the "weekend effect") was compared. The magnitude of the weekend effect was also compared among patients admitted to major teaching, minor teaching, and nonteaching hospitals.

Results: The adjusted odds of death for patients admitted on weekends when compared with weekdays was 1.03 (95% confidence interval [CI]: 1.01 to 1.06; P = 0.0050). Three diagnoses (cancer of the ovary/uterus, duodenal ulcer, and cardiovascular symptoms) were associated with a statistically significant weekend effect. None of the 50 diagnoses demonstrated a statistically significant reduction in mortality for weekend admissions as compared with weekday admissions. Mortality was similar among patients admitted to major (odds ratio [OR] = 1.06; 95% CI: 0.94 to 1.19) and minor (OR = 1.03; 95% CI: 0.97 to 1.09) teaching hospitals, compared with nonteaching hospitals. However, the weekend effect was larger in major teaching hospitals compared with nonteaching hospitals (OR =1.13 vs. 1.03, P = 0.03) and minor teaching hospitals (OR = 1.05, P = 0.11).

Conclusion: Patients admitted to hospitals on weekends experienced slightly higher risk-adjusted mortality than did patients admitted on weekdays. While overall mortality was similar for patients admitted to all hospital categories, the weekend effect was larger in major teaching hospitals and is cause for concern.