The off-hour effect in severe trauma and the structure of care delivery among Japanese emergency and critical care centers: A retrospective cohort study.

BACKGROUND: The association between mortality and off-hour presentation to a medical center has been studied in relation to various diseases and settings, but little is known of what the association indicates. This study explored the association in severe trauma patients among Japanese emergency and critical care centers and their association with the structural factors of the medical center.

METHODS: We conducted a retrospective cohort study using a Japanese, nationwide administrative database and the annual emergency and critical care centers evaluation report. We included patients who were seen because of trauma, were at least 15 years old, were transferred to an emergency and critical care center by ambulance, were admitted to the intensive care unit, and were discharged between April 1, 2012 and March 31, 2017. Off-hour care was defined as initial care beginning at all times except 8 am to 6 pm on weekdays and 8 am to noon on Saturdays. We evaluated this topic using the structure-process-outcome model as proposed by Donabedian. A multilevel logistic regression analysis was performed.

RESULTS: The sample included 111,266 patients from 233 emergency and critical care centers. The adjusted mortality odds ratio for off-hour care was 0.90 (95% confidence interval: 0.85-0.96; P < .001). In the off-hour care cohort, the immediate availability of an operating room and off-hours work management including shift work introduction had adjusted mortality odds ratios of 0.85 (95% confidence interval: 0.74-0.98; P = .02) and 0.85 (95% confidence interval: 0.73-0.99; P = .04), respectively.

CONCLUSION: In Japan, severe trauma patients who received off-hour care at the emergency and critical care centers had a decreased in-hospital mortality. The immediate availability of an operating room and management of off-hours work were contributing structural factors. Process factors in off-hour care need to be considered in future research on this topic. This finding may have important applicability to other countries as well.