Symptom Exacerbation and Adverse Events during a Randomized Trial of Early-stage Concussion Rehabilitation.

CONTEXT: Few studies utilize randomized clinical trials (RCT) to quantify clinical intervention safety of rehabilitation after sport-related concussion across sport levels. OBJECTIVE: Describe symptom exacerbation and adverse events (AEs) associated with two concussion rehabilitation interventions. DESIGN: Cluster Randomized Controlled Trial (XXX). SETTING: Sports medicine clinic and field settings. PARTICIPANTS: The RCT enrolled 251 concussed athletes (median age=20 years; female n=48) across 28 sites from New Zealand professional rugby (n=31), Canadian professional football (n=52), United States (U.S.)/Canadian colleges (n=128) and U.S. high schools (n=40). INTERVENTIONS: Two medically supervised interventions: 1) Enhanced Graded Exertion (EGE): international return to sport strategy and sport specific activities only (EGE-only n=119) and 2) Multidimensional Rehabilitation (MDR) followed by EGE: early symptom-directed exercises once symptoms were stable, followed by EGE after symptoms resolved (MDR+EGE n=132). MAIN OUTCOME MEASURES: Primary outcomes were intrasession total symptom severity score exacerbation and significant intersession (increase 10+ severity points) sustained total symptom severity exacerbation, each measured with a Postconcussion Symptom Scale (132 total severity points on scale). Reported AEs were also described. Activity-based rehabilitation sessions (n=1437) were the primary analysis unit. Frequencies, proportions, medians, and Interquartile Ranges (IQRs) were calculated for outcomes by treatment group. RESULTS: The 251 post-injury participants completed 1437 (MDR+EGE=819, EGE-only=618) activity-based intervention sessions. A total of 110 and 105 participants contributed data (those missing had no documented session data) to at least 1 activity-based session in the MDR+EGE and EGE-only arms respectively. Intrasession symptom exacerbations were equivilantly low in MDR+EGE and EGE-only arms (MDR+EGE: 16.7%, 95% CI:14.1%,19.1%; EGE-only: 15.7%, 95% CI: 12.8%,18.6%). In total, 9/819 MDR+EGE sessions (0.9%) and 1/618 EGE-only sessions (0.2%) resulted in a pre- to post-session symptom exacerbation beyond a 10+ severity point increase; 8/9 resolved to <10 points by the next session. Two study-related AEs (1 in each arm) were reported. CONCLUSIONS: Participants in MDR+EGE and EGE-only activities reported equivalently low rates of symptom exacerbation.