Socioeconomic Disparities in Concussion Presentation.

Importance: The lack of a comprehensive population-level study evaluating the association of marginalization markers with concussion presentation limits opportunities for health care system improvements. Objective: To describe the association of socioeconomic measures of disparity with location of concussion presentation and follow-up rates. Design, Setting, and Participants: This population-based cohort study used linked administrative databases to assess patients with International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Canada (ICD-10-CA) concussion diagnosis codes at emergency department (ED) or outpatient clinics in Ontario, Canada, from April 1, 2010, to March 31, 2023. Data analysis was performed from March 1, 2025, to February 8, 2026. Exposures: Patient-level exposures were age, sex, immigrant status, presence of family physician, and rurality. Neighborhood-level exposures were income quintile, Ontario Marginalization (ON-Marg) Material Resource Index (access to basic material needs, such as percentage of unemployment), Household and Dwelling Index (accommodation type, such as percentage living alone), and Racialized and Newcomer Populations Index (such as percentage of recent immigrants or those who identify as a visible minority group) within 4 different age groups (<18, 18-39, 40-64, and ≥65 years). Main Outcomes and Measures: Location of initial visit (ED vs outpatient, including urgent care, walk-in, primary care, and specialty clinic) and presence of outpatient follow-up visit at 30 days or less. Results: Overall, 674 629 patients were evaluated (356 842 [52.9%] female; mean [SD] age, 32.8 [22.0] years). Marginalization measures were higher for patients first presenting to EDs vs outpatient via the ON-Marg Material Resources Index (57 043 [20.4%] vs 56 856 [14.4%]; difference, 6.2 [95% CI, 6.0-6.3] percentage points), rurality (47 356 [16.9%] vs 35 521 [9.0%]; difference, 7.9 [95% CI, 7.8-8.1] percentage points), and presence of a family physician (264 179 [94.4%] vs 388 346 [98.3%]; difference, -3.9 [95% CI, -3.8 to -4.0] percentage points). In modeling, having a family physician was associated with first seeking care in EDs (18-39 years: odds ratio [OR], 4.71; 95% CI, 4.41-5.03), as was living in rural areas (18-39 years: OR, 1.56; 95% CI, 1.51-1.62). Follow-up rates at 30 days or earlier were lower for patients first seen in EDs (24 307 [8.7%]) vs outpatient (110 821 [28.1%]). In regression analysis assessing variables associated with follow-up, first being seen in EDs (aged 65 years: OR, 0.21; 95% CI, 0.19-0.22), not possessing a family physician (aged ≥65 years: OR, 0.29; 95% CI, 0.19-0.46), and being in the most marginalized quintile for ON-Marg Material Resources (aged ≥65 years: OR, 0.74; 95% CI, 0.65-0.84) were all significantly associated with not completing a follow-up visit. Conclusions and Relevance: In this cohort study of patients with concussion treated in Ontario, Canada, those with higher marginalization markers were more likely to first seek care in EDs and have lower follow-up rates. These findings emphasize the importance of expanding health care system-wide resources, including primary care access and telemedicine, and enhancing resources for ED clinicians to optimize concussion care.