Impact of Medicaid Expansion on Access to Opioid Analgesic Medications and Medication-Assisted Treatment

Alana Sharp, MPH; Austin Jones, MA; Jennifer Sherwood, MSPH; Oksana Kutsa, BS; Brian Honermann, JD; Gregorio Millett, MPH


Am J Public Health. 2018;108(5):642-648. 

In This Article

Abstract and Introduction


Objectives. To assess the impact of the expansion of Medicaid eligibility in the United States on the opioid epidemic, as measured through increased access to opioid analgesic medications and medication-assisted treatment.

Methods. Using Medicaid enrollment and reimbursement data from 2011 to 2016 in all states, we evaluated prescribing patterns of opioids and the 3 Food and Drug Administration–approved medications used in treating opioid use disorders by using 2 statistical models. We used difference-in-differences and interrupted time series models to measure prescribing rates before and after state expansions.

Results. Although opioid prescribing per Medicaid enrollee increased overall, we observed no statistical difference between expansion and nonexpansion states. By contrast, per-enrollee rates of buprenorphine and naltrexone prescribing increased more than 200% after states expanded eligibility, while increasing by less than 50% in states that did not expand. Methadone prescribing decreased in all states in this period, with larger decreases in expansion states.

Conclusions. The Medicaid expansion enrolled a population no more likely to be prescribed opioids than the base Medicaid population while significantly increasing uptake of 2 drugs used in medication-assisted treatment.


The United States is in the midst of an epidemic of opioid drug use, constituting one of the worst public health crises in recent history. In 2015, more than 52 000 people died from drug overdoses, and early estimates suggest continuing increases in mortality in 2016 and 2017.[1,2] Today, drug overdose is the leading cause of accidental death in the country and contributes to more deaths than do motor vehicle accidents.[3,4]

The response to rising opioid use and mortality will require increased access to evidence-based treatment options for people who use drugs. Currently, methadone, buprenorphine, and naltrexone are the only Food and Drug Administration (FDA)–approved medications produced for and used in the treatment of opioid dependence. According to the World Health Organization and Centers for Disease Control and Prevention (CDC), medication-assisted treatment (MAT) is the most effective regimen for reducing drug use and is effective in reducing overdose rates, HIV transmission, and criminal activity, while increasing treatment retention.[5,6] Yet nearly 9 out of 10 people with substance use disorders do not access treatment services, and lack of health insurance is cited as a primary barrier to accessing treatment by nearly one third of those with an identified need for treatment.[6]

Medicaid is a major funder of substance use treatment programs and in 2015 covered services for 17% of all adults with substance use disorder.[7,8] The Patient Protection and Affordable Care Act (ACA) included several provisions that increased access to substance use disorder treatment. In addition to enabling states to expand Medicaid eligibility to low-income adults, the ACA established guidance such that state benchmark plans must include a specified set of essential health benefits, including mental health and substance use disorder services.[9] In addition, the Mental Health Parity and Addiction Equity Act, which mandates that mental health services be offered at parity with other types of medical care, is expanded to apply to plans in the expansion. Previous work finds that the number of Medicaid-reimbursed prescriptions for buprenorphine increased in states that expanded Medicaid, although many low-income adults with substance use disorders in all states continue to have limited access to affordable treatment.[10] In addition, Medicaid expansion may increase access by increasing health system capacity, as shown by documented increases in the number of Drug Addiction Treatment Act of 2000–waived physicians eligible to prescribe buprenorphine in states that expanded Medicaid.[11]

While the Medicaid expansion has increased access to MAT, it may have similarly increased access to opioid analgesic medications. Historical analyses have found opioid prescribing rates for the Medicaid population to be more than double the rates for non-Medicaid enrollees, raising concerns that Medicaid expansion may inadvertently act as a driver of opioid abuse and addiction.[12] Citing increased access to pharmaceuticals as a potential driver of opioid use and addiction, both in the Medicaid population and also generally, several states have instituted policies to reduce access to opioids, including setting limits on the number of opioid pills that can be prescribed or requiring prior authorization before prescribing.[13–17]

However, despite the role of Medicaid as a major payer of substance use disorder treatment,[18] the expansion's impact on the opioid epidemic has not been sufficiently quantified. Recently, at least 1 analysis has refuted the assertion that Medicaid expansion has contributed to rising opioid use and mortality, but no previous work has quantitatively described the impact of the ACA's changes to Medicaid eligibility on both opioid drug use and treatment.[19] Using both a difference-in-differences model and an interrupted time series model, this analysis describes prescribing patterns for opioids and the 3 FDA–approved medications for opioid use disorder treatment before and after Medicaid expansion, providing an important body of evidence on the role of Medicaid programs in the opioid epidemic.