Effects of mental health reimbursement increases in Medicaid on providers and patients

Oregon Health & Science University, Portland OR

Investigators

Abstract

Project Summary One in three Medicaid enrollees has a diagnosed mental health condition, yet this population faces substantial mental health service gaps. Low Medicaid reimbursement is thought to be one key factor limiting the available mental health specialists willing to accept Medicaid enrollees, contributing to these access gaps. However, there have been strikingly few investigations on how payment amounts affect provider participation and enrollee utilization and outcomes in Medicaid. Studies drawn mostly from primary care have yielded mixed results, and it is unclear that findings in the primary care literature extend to mental health care, which faces unique systemic and workforce constraints. Without rigorous study, policies using reimbursement to address Medicaid mental health workforce shortages may fail to achieve their intended effects. Against these knowledge gaps, we propose a 5-year mixed-methods research agenda that uses national Medicaid claims data coupled with in-depth qualitative interviews to leverage a real-world natural experiment: beginning in 2022, multiple state Medicaid programs have implemented reimbursement increases for mental health services in an effort to expand the mental health workforce and improve access to care. This explanatory sequential mixed methods proposal thus focuses on key questions critical to policymakers: 1) to what extent do mental health reimbursement rate increases change provider behavior and patient health, and 2) under what conditions do they work well? In Aims 1 and 2, we use 2016-2025 national Transformed Medicaid Statistical Information System (T-MSIS) Analytic Files (TAF), which provides comprehensive enrollee-level claims data related to service utilization and prescription use. We use an event study difference-in-differences framework to assess changes in outcomes for Medicaid enrollees exposed to reimbursement increases across dimensions of magnitude (how large are rate increases?) and scope (to what services do rate increases apply?). Aim 3 provides added explanatory depth on the policy heterogeneity of reimbursement rate increases, through key informant interviews with state Medicaid administrators and mental health providers. We will select up to 8 states where reimbursement increases are associated with improvements in Medicaid provider participation (positive deviance states), and 8 states where they are not (negative deviance states). A number of innovations, including assessment of policy heterogeneity across states, consideration of market factors and claims-based measures of administrative burdens that influence provider decisions, and inclusion of both psychiatrists and psychiatric mental health nurse practitioners, provide a comprehensive and robust assessment of mental health rate increases, a key priority for state Medicaid programs and policymakers. In collaboration with an advisory committee of Medicaid and mental health policy stakeholders, results will provide actionable, impactful evidence to guide timely policies within a constrained mental health delivery system. 1