Race, Region, and Reimbursement: Sociodemographic Variations in Medicare Payments for Spine Surgery in the United States, 2014-2022.

Study design: Retrospective.

Objective: Assess whether Medicare adjustments adequately correct for systemic population-level payment variations.

Summary of background data: Medicare currently uses payment adjustments for spine surgery, including clinical risk, geography, and socioeconomic status.

Methods: Using Medicare fee-for-service claims from 2014 to 2022, we conducted a retrospective cohort study of spine-related diagnosis-related groups (459 state-year observations). Multivariable regression models examined associations between payments and sociodemographic factors, controlling for existing Medicare adjustments.

Results: Significant disparities persisted despite adjustment. Each percentage-point increase in Black beneficiaries was associated with $172 higher payments (95% CI: $111-$232, P<0.001), while Hispanic population increases showed the opposite effect (-$174 per point; 95% CI: -$252 to -$96, P<0.001). Areas with above-median female proportions had $1596 higher payments (95% CI: $580-$2611, P=0.002). Regional variations were notable: payments were higher in the West ($11,060), Northeast ($5762), and Midwest ($3210) than in the South (all P<0.001).

Conclusions: Medicare payments for inpatient spine care demonstrate persistent demographic disparities unaddressed by current risk-adjustment models. Future research should determine whether these variations indicate appropriate adjustments for care needs or systematic underpayment or overpayment for the treatment of particular populations.