Geographic and Racial Disparities in Behavioral Health Services in Michigan Medicaid

Date of Award

5-2026

Degree Name

Doctor of Philosophy

Department

Interdisciplinary Health Sciences

First Advisor

Rob Lyerla, Ph.D.

Second Advisor

Renée Branch Canady, Ph.D.

Third Advisor

Kieran Fogarty, Ph.D.

Abstract

Persistent geographic and racial disparities in healthcare access and outcomes represent a significant public health challenge in the United States, particularly within the Medicaid population, which faces greater barriers to care and fewer available supports than the general population. This study investigates the extent and nature of geographic and racial disparities in behavioral health services within the Michigan Medicaid program, focusing on three counties — Wayne, Kent, and Ingham — between 2018 and 2020. These counties were selected to capture variation across size, geographic location, and income across the state.

Using Medicaid claims and encounter data, the study uses two standardized quality measures: follow-up after emergency department visits for mental illness (FUM), defined as receiving a follow-up visit within 30 days of an Emergency Department (ED) visit with a principal diagnosis of mental illness or intentional self-harm; and initiation and engagement in treatment for substance use disorder (IET), defined as initiating treatment and engaging in ongoing care within 34 days of a new diagnosis. These measures are compared between Black/African American and White Medicaid beneficiaries, with White beneficiaries serving as the reference population. Only individuals with full-coverage Medicaid for at least one calendar year in the study period were included in the analysis.

Pairwise t-test analyses reveal significant racial disparities in both measures across multiple counties and years, with Black/African American Medicaid beneficiaries consistently less likely than their White counterparts to receive clinically appropriate care. Racial disparities in the IET measure were significant across all three counties in both 2018 and 2020. The magnitude of the IET disparity grew between study years in Wayne (2.9 to 8.1 percentage points) and Kent (4.6 to 7.0 percentage points) counties, while remaining stable in Ingham County (8.1 percentage points in both years). For the FUM measure, significant racial disparities were found in Wayne County in both years, while Kent and Ingham counties showed no significant racial disparity in either year, a finding that diverges from prior national literature and may be reflective of county-level variation in provider networks, infrastructure, or local initiatives.

Difference-in-difference-in-differences (DiDiD) analysis, which examined three-way interaction effects of race, county, and year, yielded non-significant findings for both the FUM and IET measures, indicating that the combined influence of these three factors did not meaningfully shift quality measure rates across the study period. The results, in alignment with previous studies, underscore the persistence of racial inequities in behavioral health access, particularly for substance use disorder services, and point to the role of structural determinants — including provider participation, administrative barriers, stigma, and systemic racism — in shaping treatment access and outcomes. The substantially lower rates for the IET measure compared to the FUM measure across all counties and years suggest that these additional factors may play a particularly influential role in keeping individuals from receiving substance use disorder treatment.

Access Setting

Dissertation-Abstract Only

Restricted to Campus until

5-2028

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