Predictors of delayed recovery following pediatric sports-related concussion: a case-control study
Authors: Miller Joseph H. , Gill Clarence , Kuhn Elizabeth N. , Rocque Brandon G. , Menendez Joshua Y. , O'Neill Jilian A. , Agee Bonita S. , Brown Steven T. , Crowther Marshall , Davis R. Drew , Ferguson Drew , Johnston James M. 
Published: December 2015

OBJECT
Pediatric sports-related concussions are a growing public health concern. The factors that determine injury severity and time to recovery following these concussions are poorly understood. Previous studies suggest that initial symptom severity and diagnosis of attention deficit hyperactivity disorder (ADHD) are predictors of prolonged recovery (> 28 days) after pediatric sports-related concussions. Further analysis of baseline patient characteristics may allow for a more accurate prediction of which patients are at risk for delayed recovery after a sports-related concussion.

METHODS
The authors performed a single-center retrospective case-control study involving patients cared for at the multidisciplinary Concussion Clinic at Children's of Alabama between August 2011 and January 2013. Patient demographic data, medical history, sport concussion assessment tool 2 (SCAT2) and symptom severity scores, injury characteristics, and patient balance assessments were analyzed for each outcome group. The control group consisted of patients whose symptoms resolved within 28 days. The case group included patients whose symptoms persisted for more than 28 days. The presence or absence of the SCAT2 assessment had a modifying effect on the risk for delayed recovery; therefore, stratum-specific analyses were conducted for patients with recorded SCAT2 scores and for patients without SCAT2 scores. Unadjusted ORs and adjusted ORs (aORs) for an association of delayed recovery outcome with specific risk factors were calculated with logistic regression analysis.

RESULTS
A total of 294 patients met the inclusion criteria of the study. The case and control groups did not statistically significantly differ in age (p = 0.7). For the patients who had received SCAT2 assessments, a previous history of concussion (aOR 3.67, 95% CI 1.51–8.95), presenting SCAT2 score < 80 (aOR 5.58, 95% CI 2.61–11.93), and female sex (aOR 3.48, 95% CI 1.43–8.49) were all associated with a higher risk for postconcussive symptoms lasting more than 28 days. For patients without SCAT2 scores, female sex and reporting a history of ADHD significantly increased the odds of prolonged recovery (aOR 4.41, 95% CI 1.93–10.07 and aOR 3.87, 95% CI 1.13–13.24, respectively). Concussions resulting from playing a nonhelmet sport were also associated with a higher risk for prolonged symptoms in patients with and without SCAT2 scores (OR 2.59, 95% CI 1.28–5.26 and OR 2.17, 95% CI 0.99–7.73, respectively). Amnesia, balance abnormalities, and a history of migraines were not associated with symptoms lasting longer than 28 days.

CONCLUSIONS
This case-control study suggests candidate risk factors for predicting prolonged recovery following sports-related concussion. Large prospective cohort studies of youth athletes examined and treated with standardized protocols will be needed to definitively establish these associations and confirm which children are at highest risk for delayed recovery.