Effects of optimal versus suboptimal median household income on the surgically treated traumatic brain injury population at a level I trauma center in the Boston metropolitan area: a propensity score-matched analysis

Objective: The median household income is a useful metric for healthcare disparity assessment. New England holds the highly diverse, densely populated Boston metropolitan area, which is known for having one of the highest living wages in the US. To the authors' knowledge, there is no published data on the effects of optimal versus suboptimal median household income on the surgical treatment of patients with traumatic brain injury (TBI). The authors sought to evaluate the disparities of an optimal versus suboptimal median household income-stratified population of patients with TBI who underwent surgical treatment at a single level I trauma center with a high safety-net burden in a major US metropolitan area.

Methods: Demographic, clinical, and outcome data of patients who underwent surgery for TBI between 2015 and 2021 were collected and stratified based on optimal (≥ $80,000) and suboptimal (< $80,000) median residential household income. One-to-one tight caliper (0.01) propensity score matching was performed to balance the groups for comparative analysis.

Results: From the initial 144 patients in the optimal and 140 patients in the suboptimal income groups, 53 patients were included in each group after propensity matching. The suboptimal income group was significantly more ethnically diverse (p = 0.02), with significantly more ethnic minority patients (p = 0.05). Significantly more patients in the optimal income group presented as transfers from other hospitals (p < 0.001). Insurance status, injury mechanism, type and location, imaging features, length of ICU stay, and distribution of disposition destinations, as well as the follow-up time and outcome measures were not significantly different between the two groups after propensity matching.

Conclusions: Although the suboptimal income group is significantly more ethnically diverse, median household income does not seem to affect TBI outcomes and discharge disposition. Patients in the optimal income group more frequently presented as transfers from other facilities, potentially indicating fair high-level care at a specialized trauma center with a high safety-net burden adapted to a diverse patient population.