Medicaid Expansion and Veterans' Reliance on the VA for Depression Care.

Background: In 2001, before the Affordable Care Act (ACA), some states expanded Medicaid coverage to include an array of mental health services, changing veterans' reliance on US Department of Veterans Affairs (VA) services.

Methods: Using Medicaid and VA administrative data from 1999 to 2006, we used a difference-in-difference design to calculate shifts in veterans' reliance on the VA for depression care in New York and Arizona after the 2 states expanded Medicaid coverage to adults in 2001. Demographically matched, neighbor states Pennsylvania and New Mexico/Nevada were used as paired comparisons, respectively. Fractional logit was used to capture the distribution of inpatient and outpatient depression care utilization between the VA and Medicaid, while ordered logit and negative binomial regressions were applied to model Medicaid-VA dual users and per capita utilization of total depression care services, respectively.

Results: Medicaid expansion was associated with a 9.50 percentage point (pp) decrease (95% CI, -14.61 to -4.38) in reliance on the VA for inpatient depression care among service-connected veterans and a 13.37 pp decrease (95% CI, -21.12 to -5.61) among income-eligible veterans. For outpatient depression care, VA reliance decreased by 2.19 pp (95% CI, -3.46 to -0.93) among income-eligible veterans. Changes among service-connected veterans were nonsignificant (-0.60 pp; 95% CI, -1.40 to 0.21).

Conclusions: After Medicaid expansion, veterans shifted depression care away from the VA, with effects varying by health care setting, income- vs service-related eligibility, and state of residence. Issues of overall cost, care coordination, and clinical outcomes deserve further study in the ACA era of Medicaid expansions.