Preinjury and Postinjury Factors That Predict Sports-Related Concussion and Clinical Recovery Time.

Objectives: To evaluate the relationship between preinjury risk factors (RFs) and subsequent occurrence of concussion and examine whether preinjury RFs or postinjury assessments predict clinical recovery in collegiate athletes.

Methods: Risk factors (sex, sport, and self-report history of concussion, migraine, attention-deficit disorder, learning disability, depression, and anxiety) and Sport Concussion Assessment Tool (SCAT), depression/anxiety screenings, and neuropsychological testing were obtained before the season. For athletes who sustained concussion, RFs, postinjury SCAT, neuropsychological assessment, and clinical recovery were assessed.

Results: We assessed 1152 athletes (69% male) at baseline and 145 (75% male) after subsequent concussion diagnosis. Only sport type (Wald = 40.29, P = 0.007) and concussion history (Wald = 9.91, P = 0.007) accounted for unique variance in subsequent concussion. Of athletes followed until full recovery, mean days until symptom-free (DUSF) was 9.84 ± 11.11 days (n = 138, median = 5 days, range = 1-86) and mean days until full return to play (DUFRTP) was 20.21 ± 19.17 (n = 98, median = 20.21, range = 4-150). None of the RFs or baseline testing measures were associated with DUSF or DUFRTP (P's > 0.05). After injury, athletes who reported more total symptoms (rs = 0.31, P < 0.001) and higher symptom severity (rs = 0.33, P < 0.001) exhibited longer DUSF. Days until symptom-free correlated with DUFRTP (rs = 0.75, P < 0.001). Among athletes assessed within 2 days after injury, DUSF was associated with Immediate Postconcussion Assessment and Cognitive Test visual motor (rs = -0.31, P = 0.004), reaction time (rs = 0.40, P < 0.001), and symptom score (rs = 0.54, P < 0.001).

Conclusions: Only sport type and concussion history predicted subsequent occurrence of concussion, and none of the RFs or baseline measures predicted clinical recovery. Immediate postinjury assessments, including symptom number and severity, and select clinical measures predicted longer clinical recovery.