The expansion of Medicaid coverage for low-income adults permitted by the Affordable Care Act (ACA) was associated with a six percent reduction in total opioid overdose deaths nationally, according to new research from the University of California, Davis, Violence Prevention Research Program and the NYU Grossman School of Medicine.
Published online January 10 in JAMA Network Open, the study is the first to look at whether the ACA-related Medicaid expansion is associated with county-level opioid overdose mortality.
"We know that states and local communities play an important role in preventing opioid overdose deaths," said Nicole Kravitz-Wirtz, lead author of the study and an assistant professor with the Violence Prevention Research Program at UC Davis. "Our findings suggest that in states that opted to expand Medicaid coverage, thousands of lives may have been saved as a result."
For the study, the researchers analyzed cause-of-death data from the National Vital Statistics System from 3,109 counties within 49 states and the District of Columbia between 2001 and 2017. They looked at changes in opioid overdose rates in counties that expanded Medicaid and compared those to changes that occurred in the same time period in counties within states that did not expand Medicaid.
Drug overdose remains a leading cause of injury death in the U.S. and is responsible for more than 70,000 deaths annually. After examining the association of Medicaid expansion with county-by-year counts of opioid overdose deaths and by class of opioid, the researchers found that:
- Medicaid expansion may have prevented between 1,678 and 8,132 opioid overdose deaths in 2015 to 2017 in the 32 states that expanded Medicaid between 2014 and 2016.
- Adoption of Medicaid expansion was associated with a six percent lower rate of total opioid overdose deaths, 11 percent lower rate of death involving heroin, and a 10 percent lower rate of death involving synthetic opioids other than methadone (such as fentanyl).
- Unexpectedly, an 11 percent increase in methadone overdose mortality was observed with Medicaid expansion.
"Our findings suggest that as states invest more resources in addressing the opioid overdose epidemic, policymakers should pay attention to the role that expanding Medicaid can play in reducing opioid overdose deaths by providing greater access to health care, and in particular, to treatment for opioid use disorder," said Magdalena Cerdá, associate professor and director of the Center for Opioid Epidemiology and Policy in the Department of Population Health at NYU Langone Health, and the study's senior author. "At a broader level, the findings of this study suggest that providing expanded access to health care may be a key policy lever to address the opioid overdose crisis."
One concerning finding from the study was the association of Medicaid expansion with an 11 percent increase in overdose deaths involving methadone. According to Cerdá, Medicaid beneficiaries are more likely to receive prescriptions for methadone to treat pain, compared to the general population. While the dispensing of methadone to treat opioid use disorder is highly effective and standardized, the use of methadone to treat pain is associated with greater risk of overdose reflecting in part wide variation in prescribing practices.
"Past research has found Medicaid expansion is associated with not only large decreases in the number of uninsured Americans, but also considerable increases in access to opioid use disorder treatment and the opioid overdose reversal medication naloxone," Kravitz-Wirtz said. "Ours was the first study to investigate the natural follow-up question: Is the expansion associated with reductions in local opioid overdose deaths? On balance, the answer appears to be, yes."
Study Limitations
Cerdá and colleagues cite a number of study limitations. First, the research relies on coding of death certificate data. Since coding has changed over time, some deaths due to opioid overdoses may be misclassified. A second limitation is that the investigators looked at deaths among the whole population as opposed to just Medicaid beneficiaries. Any effect detected may be an underestimate of the effect that would be observed among Medicaid beneficiaries.
Finally, although the researchers looked at the relationship of Medicaid expansion and overdose mortality, they did not directly examine pathways such as how Medicaid expansion affects access to treatment for opioid use disorder, how it affects opioid misuse and nonfatal overdoses, or how it affects access to naloxone, a medication used to counter the effects of opioid overdose. Each of these additional pathways are worthy of future study and are likely important levers to pull in terms of addressing the opioid overdose crisis.
Other study co-authors include Corey S. Davis from the Network for Public Health Law, William R. Ponicki of the Prevention Research Center at Pacific Institute for Research and Evaluation, Ariadne Rivera-Aguirre at NYU Langone, Brandon Marshall at Brown University School of Public Health, and Silvia S. Martins at the Mailman School of Public Health, Columbia University.
Funding for the study was provided by the National Institute on Drug Abuse, grant number 1R01DA039962-01. Additional support for individual authors came from the National Institute of General Medical Sciences (P20-GM125507) and the UC Davis Violence Prevention Research Program.
The UC Davis Violence Prevention Research Program focuses on the causes, consequences and prevention of violence. Studies assess firearm violence, the social conditions that underlie violence, and the connections between violence and mental illness. VPRP is home to the University of California Firearm Violence Research Center, which launched in 2017 with a $5 million appropriation from the state of California to conduct leading-edge research on firearm violence and its prevention.
