Use of behavioral health care in Medicaid managed care carve-out versus carve-in arrangements

Objective: To evaluate differences in access to behavioral health services for Medicaid enrollees covered by a Medicaid entity that integrated the financing of behavioral and physical health care ("carve-in group") versus a Medicaid entity that separated this financing ("carve-out group").

Data sources/study setting: Medicaid claims data from two Medicaid entities in the Portland, Oregon tri-county area in 2016.

Study design: In this cross-sectional study, we compared differences across enrollees in the carve-in versus carve-out group, using a machine learning approach to incorporate a large set of covariates and minimize potential selection bias. Our primary outcomes included behavioral health visits for a variety of different provider types. Secondary outcomes included inpatient, emergency department, and primary care visits.

Data collection: We used Medicaid claims, including adults with at least 9 months of enrollment.

Principal findings: The study population included 45,786 adults with mental health conditions. Relative to the carve-out group, individuals in the carve-in group were more likely to access outpatient behavioral health (2.39 percentage points, p < 0.0001, with a baseline rate of approximately 73%). The carve-in group was also more likely to access primary care physicians, psychologists, and social workers and less likely to access psychiatrists and behavioral health specialists. Access to outpatient behavioral health visits was more likely in the carve-in arrangement among individuals with mild or moderate mental health conditions (compared to individuals with severe mental illness) and among black enrollees (compared to white enrollees).

Conclusions: Financial integration of physical and behavioral health in Medicaid managed care was associated with greater access to behavioral health services, particularly for individuals with mild or moderate mental health conditions and for black enrollees. Recent changes to incentivize financial integration should be monitored to assess differential impacts by illness severity, race and ethnicity, provider types, and other factors.