To quantify the risk of repeat concussions for children and identify demographic and clinical aspects of the index concussion associated with repeat injury.
For this retrospective cohort study, we queried the Children's Hospital of Philadelphia healthcare network's unified electronic health record to identify all 5- to 15-year-old patients who had their first clinical visit for an index concussion at a Children's Hospital of Philadelphia location from July 2012 through June 2013. A 25% random sample (n = 536) were selected. Clinical data were abstracted for their index concussion and all concussion-related visits for 2 years following the index concussion.
Overall, 16.2% (n = 87) of patients experienced at least 1 repeat concussion within 2 years of their index concussion. The risk of repeat concussion increased with patient age (9.5% for ages 5-8 years; 10.7% for ages 9-11 years; and 19.8% for ages 12-15 years). After we adjusted for other factors, risk was particularly heightened among patients whose index concussion had a longer clinical course (>30 vs 0-7 days, adjusted risk ratio 1.65 [1.01-2.69]) and greater symptom burden (>11 vs 0-2 symptoms, adjusted risk ratio 2.12 [1.12-3.72]).
We estimate that 1 in 6 youth diagnosed with a concussion are diagnosed with a subsequent concussion within 2 years and that several clinical characteristics of the index concussion increase this risk. Identifying factors associated with a repeat injury is essential to inform the clinical management of concussion and direct injury prevention efforts.