878 FO49 – 49% higher risk of subsequent injury after sports-related concussion in professional male rugby union: a ten-year cohort study

Background Subsequent injury (SI) rates after concussion have been shown to be higher than after non-concussion injuries in a range of sports. Objectives Investigate whether there is an increased rate of any SI, and/or difference in median survival time to any SI, after concussion compared to after non-concussion injuries. Explore whether there is a change in rates of any SI, and/or median survival time to any SI, over ten seasons. Design Prospective cohort study. Setting Professional male rugby union. Participants Professional men's 1st team players in English Premiership teams. Assessment of Risk Factors Exposure to concussion. Main Outcome Measurements Incidence rate ratios (IRR) comparing SI rates pre- and post- players' first concussion in a season and SI rates in players not sustaining a concussion. Median survival time to any SI after concussion compared to non-concussion injury. Linear regression to determine changes over time. Results A total of 5921 injuries (1105 concussions) were reported in 77439 match hours (6266 player seasons). Match concussion incidence was 14.3 per 1000 hours, mean severity was 16.9 days lost per injury. The IRR of SI was higher post-concussion vs non-concussion injury (IRR=1.49, CI 1.38–1.61), and vs pre-concussion (IRR=1.57, CI 1.40–1.76), with no difference pre-concussion vs non-concussion injury (IRR=0.95, CI 0.86–1.05). Median survival time was 133 days following concussion and 169 days following non-concussion injury (p=0.002, Exp(ß)=1.19, CI=1.07–1.32). There was no change over time in IRR of SI (ß=61.733, p=0.215), nor in median survival to SI (ß=0.224, p=0.962). Conclusions The rate of any SI after concussion was consistently higher, with significantly shorter time to any SI, than after non-concussion injuries over ten-seasons. Further work to understand whether specific signs or symptoms of concussion influence SI rates, or whether a more conservative approach to return to play from concussion reduces SI rates, will inform future concussion management.