The off-hour effect among severe trauma patients: a nationwide cohort study in Japan.

Abstract

To assess whether there are temporal differences altering the clinical outcomes of severe trauma patients in Japan. This was a retrospective cohort study that used recorded data from the Japan Trauma Data Bank. Severe trauma patients who had an injury severity score of greater than 16 were included. The hospital arrival time was categorized into daytime (8 a.m.-7:59 p.m.) and nighttime (8 p.m.-7:59 a.m.). The hospital arrival day of the week was categorized into business days and non-business days. The primary outcome was in-hospital mortality. A total of 65,136 severe trauma patients were analyzed. In-hospital mortality was 15.6% in the daytime and 14.4% in the nighttime, and 15.5%, and 14.6% on business days and non-business days, respectively. Nighttime was associated with decreased in-hospital mortality compared to daytime (odds ratio = 0.817, 95% confidence interval = 0.764-0.874) and a non-business day was not associated with in-hospital mortality. We did not find a negative off-hour effect on in-hospital mortality among severe trauma patients.