Geographic characteristics of sport- and non-sport-related concussions presenting to emergency departments in the United States

Background: Concussion is a type of traumatic brain injury (TBI) that can be sustained through sport-related and non-sport-related (e.g., motor vehicle accidents, falls, assaults) mechanisms of injury (MOI). Variations in concussion incidence and MOI may be present throughout the four geographic regions (Midwest, Northeast, South, West) of the United States. However, there is limited evidence exploring concussion cause and diagnosis patterns based on geographic region and MOI. These factors have implications for better understanding the burden of concussion and necessary efforts that can translate to the mitigation of safety concerns. Purpose: The purpose of this study was to identify patterns of sport-related concussion (SRC) and non-sport-related concussion (NSRC) across the four geographic regions of the United States. Methods: A descriptive epidemiology study of patient visits to the emergency department (ED) for concussion between 2010 and 2018, using publicly available data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) was conducted. The exposure of interest was geographic region while the main outcome measures were concussion diagnosis and MOI. Descriptive statistics were calculated using population-weighted frequencies and percentages. The association between geographic region and MOI (SRC vs. NSRC) was analyzed using logistic regression models. Odds ratios (OR) presented with 95% confidence intervals (CI) were included. Univariate analyses were conducted followed by multivariable analyses adjusting for sex, age, race/ethnicity, and primary source of payment. Statistical significance was set a priori at p < 0.05 for all analyses. Results: From 2010 to 2018, 1,161 visits resulted in a concussion diagnosis, representing an estimated 7,111,856 visits nationwide. A greater proportion of concussion diagnoses occurred within EDs in the South (38.2%) followed by the West (25.8%), Midwest (21.4%), and Northeast (14.6%). Compared to the West region, patients visiting the ED in the Midwest (OR = 0.75, 95% CI = 0.57–0.98) and Northeast (OR = 0.71, 95% CI = 0.51–0.98) had a lower odds of being diagnosed with a concussion. More patients sustained a NSRC MOI (94.3%) compared to SRC MOI (5.7%). For both mechanisms, the South region had the highest population-weighted frequency of SRC (n = 219,994) and NSRC diagnoses (n = 2,495,753). Univariate and multivariable logistic regression analyses did not reveal statistically significant associations for geographic region and MOI (p > 0.05). Conclusion: Our findings showed that the Midwest and Northeast regions had a lower odds of concussion diagnoses in EDs. Overall, the vast majority of concussions were not sport-related, which has public health implications. These findings improve our understanding of how concussion injuries are being sustained geographically nationwide and help to explain care-seeking patterns for concussion in the ED setting.