A-14 Clinical Outcome Following Concussion Among College Athletes with a Prior Concussion History: A Systematic Review

Abstract

Abstract Purpose: This systematic review examined the association between prior concussion history and clinical outcomes following concussion among collegiate athletes. Methods: This review was registered with PROSPERO database for systematic reviews (protocol ID: CRD42016041479 & CRD42019128300) and adhered to PRISMA guidelines. Three searches of nine online databases were conducted: (1) database inception to June of 2016; (2) January 1, 2016 to February 1, 2019; and (3) February 1, 2019 to May 15, 2021. We screened 5118 abstracts and 619 full-text articles were reviewed. We utilized a likelihood heuristic to assess evidence for an association between concussion history and clinical outcomes. Results: Sixteen studies met inclusion criteria, and 13 studies reported the number of participants with a history of prior concussions (≥1)—which totaled 1690 of 4573 total participants (37.0%). Newcastle-Ottawa risk of bias ratings ranged from 3 to 9 (mean = 5.4, SD = 1.4). Across all studies, 43.8% (k = 7/16) reported a statistically significant result among primary analyses showing an association between concussion history and worse clinical outcome. A minority of studies reporting on symptom duration (4/13, 30.8%) and time to return to play (2/7, 28.6%) found an association between concussion history and worse outcome. Conclusions: The question of whether college athletes with a history of concussion have, on average, worse clinical outcome from their next concussion remains unresolved. Many studies to date are small, and only three focused specifically on this topic. Important clinical outcomes, such as time to return to academics, have not been adequately studied. Larger hypothesis-driven studies are needed.