Hospital Medicaid payer mix associated with inpatient mortality following traumatic brain injury.

BACKGROUND

Disparities in traumatic brain injury (TBI) outcomes are well-documented at the patient level, but less is known about how hospital-level Medicaid burden influences outcomes after TBI. We investigated whether hospitals with a higher Medicaid payer mix were associated with poorer outcomes for patients with TBI.

METHODS

Using the ACS TQIP data set, we performed a retrospective cohort study of adult patients with TBI. We calculated the proportion of Medicaid-insured patients at each hospital and classified hospitals into quartiles of advancing Medicaid payer mix. Risk-adjusted multivariable logistic regression models investigated the relationships between hospital quartile and inpatient mortality and favorable discharge (ie, to home or inpatient rehabilitation). Effect modification was tested between hospital quartile, patient age, and race. We repeated these models after propensity score matching between quartile 1 (Q1, least Medicaid) and quartile 4 (Q4, most Medicaid) hospitals, and again among a subgroup of patients younger than 65 years.

RESULTS

Among 384,394 patients treated across 737 hospitals, 13% (N=50,493) were Medicaid-insured. Hospitals had a median Medicaid payer mix of 9.9% (IQR, 5.9%-16%). Treatment at Q4 hospitals was associated with higher risk-adjusted odds of inpatient mortality (OR, 1.30; 95% CI, 1.24-1.36). This effect was amplified with increasing age ( p <0.001; Q4: OR, ≥65 vs. <65 y, 1.34 [1.26-1.42] vs. 1.17 [1.08-1.26]) but was diminished for black patients ( p =0.02; Q4: OR, black vs. white, 1.13 [0.98-1.31] vs. 1.32 [1.25-1.39]). After matching, patients treated at Q4 hospitals had higher odds of inpatient mortality (OR, 1.31; 95% CI, 1.25-1.38) and lower odds of favorable discharge (OR, 0.85; 95% CI, 0.83-0.87), and these associations persisted in the subgroup of patients younger than 65 years.

CONCLUSIONS

Hospitals serving a higher proportion of Medicaid-insured patients were associated with poorer outcomes after TBI. These findings highlight the importance of addressing hospital-level disparities in trauma care delivery. ( J Trauma Acute Care Surg . 2026;101: 644-654.).

LEVEL OF EVIDENCE: Prognostic and Epidmiologic; Level III.