The effects of behavioral health integration in Medicaid managed care on access to mental health and primary care services-Evidence from early adopters.

Objective: To evaluate the impacts of a transition to an "integrated managed care" model, wherein Medicaid managed care organizations moved from a "carve-out" model to a "carve-in" model integrating the financing of behavioral and physical health care.

Data Sources/study Setting: Medicaid claims data from Washington State, 2014-2019, supplemented with structured interviews with key stakeholders.

Study Design: This mixed-methods study used difference-in-differences models to compare changes in two counties that transitioned to financial integration in 2016 to 10 comparison counties maintaining carve-out models, combined with qualitative analyses of 15 key informant interviews. Quantitative outcomes included binary measures of access to outpatient mental health care, primary care, the emergency department (ED), and inpatient care for mental health conditions.

Data Collection: Medicaid claims were collected administratively, and interviews were recorded, transcribed, and analyzed using a thematic analysis approach.

Principal Findings: The transition to financially integrated care was initially disruptive for behavioral health providers and was associated with a temporary decline in access to outpatient mental health services among enrollees with serious mental illness (SMI), but there were no statistically significant or sustained differences after the first year. Enrollees with SMI also experienced a slight increase in access to primary care (1.8%, 95% CI 1.0%-2.6%), but no sustained statistically significant changes in the use of ED or inpatient services for mental health care. The transition to financially integrated care had relatively little impact on primary care providers, with few changes for enrollees with mild, moderate, or no mental illness.

Conclusions: Financial integration of behavioral and physical health in Medicaid managed care did not appear to drive clinical transformation and was disruptive to behavioral health providers. States moving towards "carve-in" models may need to incorporate support for practice transformation or financial incentives to achieve the benefits of coordinated mental and physical health care.