Impact of Medicaid Expansion on Treatment Admissions Involving Opioid Use in Residential Substance Use Treatment Settings

Introduction: With opioid overdose deaths rising to their highest level in 2022, the economic and societal costs of the current opioid epidemic are high. While medications for opioid use disorder (MOUD) are effective in reducing overdose risk and promoting recovery, most people do not receive any medication treatment. Residential treatment programs have been slow to adopt MOUD relative to outpatient treatment due to differences in treatment philosophy and insurance restrictions. Implemented in 2014 under the Affordable Care Act, Medicaid Expansion is a potential mechanism to increase access to MOUD in residential treatment. Yet, few studies have examined the impact of Medicaid Expansion on MOUD use in residential treatment settings. The present study uses a national dataset to first examine the impact of Medicaid Expansion on opioid-related treatment admissions and the use of MOUD in short-term and long-term residential treatment.

Methods: The primary data source for this analysis was the 2009-2020 Treatment Episode Dataset-Admissions, a publicly available administrative dataset containing treatment admissions collected annually from state health agencies by Substance Abuse and Mental Health Services Administration (SAMHSA). We restricted our analysis to admissions (n=1,106,329) involving heroin or other opioids as the primary substances at admission to specialty short- and long-term residential treatment. We used a difference-in-differences design to estimate the differential change in treatment admission rates and MOUD access, with expansion states as the treatment group (1) and non-expansion states (0) as the comparison. Linear probability models were used for ease of interpretation. We adjusted regression models for state effects as well as theoretically-relevant covariates. Models used robust jackknife standard errors. We report estimates as significant if p < .05.

Results: Approximately 14% of Medicaid Expansion states reported opioid-involved treatment admissions that had MOUD as part of their treatment plan. While most short-term programs reported MOUD use, less than half of all long-term treatment programs reported such use. The multivariate models show a significant increase in opioid treatment admissions for both short- and long-term residential treatment by 3.8% and 2.5%, respectively, in Medicaid Expansion states versus non-Expansion states between 2014-2020 versus 2009-2013. Notably, MOUD use significantly increased by 8.9% for short-term residential treatment in Medicaid Expansion versus non-Expansion states in 2014-2020 compared to 2009-2013, but no such significant increase was found in long-term residential treatment programs.

Conclusions and Implications: The current study provides further evidence of the benefits of Medicaid Expansion in facilitating access to residential treatment services. Our results underscore the importance of addressing insurance-related barriers as a strategy for increasing specialty treatment for opioid use disorder. Future research is needed to explore whether these improvements in service access as a function of Medicaid Expansion are evident in groups underrepresented in the treatment system.