Purpose: Patient care may be inconsistent during off hours. We sought to determine whether adults admitted to or discharged from intensive care units (ICUs) on evenings and weekends have increased mortality rates.
Materials and methods: All adults admitted to ICUs in the Calgary Health Region, Alberta, Canada, during 2000 to 2006 were included. The in-hospital mortality risk was assessed with admissions or discharges on weekdays (Monday to Friday) and daytime (8:00 am to 5:59 pm) as compared with weekends (Saturday and Sunday) and nights (6:00 pm to 7:59 am).
Results: Intensive care unit admissions (n = 20466) occurred during weekends in 18%, nights in 41%, and nights and/or weekends in 49%. Among the 17864 survivors to ICU discharge, 26% were discharged on weekends, 21% at night, and 41% on nights and/or weekends. Increased crude mortality rates were associated with both admission (24% vs 14%, P < .0001) and discharge (12% vs 5%, P < .0001) during nights as compared with days. Admission to (26% vs 16%, P < .0001) but not discharge from (6% vs 7%, P = .42) ICU during weekends as compared with weekdays was associated with increased mortality. After controlling for confounding variables using logistic regression analyses, neither weekend admission nor discharge was associated with death. However, both night admission and discharge were independently associated with mortality.
Conclusions: Our observations of excess risk associated with admission to or discharge from ICU at night merits further exploration as to whether it may reflect inconsistencies in care after hours.