Absence of July effect on trauma outcomes at the start of the academic medical calendar

Purpose: The "July effect" refers to the phenomenon of a higher complication incidence and lower survival rate for patients treated at academic institutions during the beginning of the academic medical calendar. To date, no multi-center study has examined the presence of a "July effect" in a large cohort of trauma patients. We sought to determine if there is a by-month effect on survival and length of stay (LOS) for trauma patients in large academic centers.Methods: We performed a multicenter, retrospective cohort study between 2010 and 2020 from five high-volume academic trauma centers in the United States. We included all adult motor vehicle collision (MVC) traumas evaluated at all centers in the study population (age >16 years, mechanism of injury classified as "motor vehicle collision"). Data included date and time of injury, injury severity score (ISS), LOS, and mortality. Each injury was classified as minor (ISS 1-8), moderate (9-15), severe (16-24), and very severe (>25). The mortality and LOS for each range over the entire epoch was calculated by month for each ISS classification.Results: We analyzed 39,668 MVC traumas (mean age 41.83, range 39.9-43.3 among sites, 58.9% male and range 56.1-60.4%, 67.4% white range 42.3-84.7%). Survival for the "very severe" traumas ranged from 86.7-90.3%. Across the five sites, there was no significant change in survival (either increased or decreased mortality) or LOS for MVC patients in July or August for any injury classification level. Both age and ISS had a significant effect on survival (OR 0.02 for ISS >25, 0.22 for patients >65 years-old, both p < 0.05).Conclusions; In five high-volume centers, there was no significant effect of the July transition on survival or LOS of MVC trauma patients.