The Impact of the Affordable Care Act Medicaid Expansions on Mortality

Medicaid expansion under the Affordable Care Act (ACA) has been shown to increase health insurance coverage and use of healthcare services as well as improve certain measures of health. It takes time for the effects of insurance coverage on health outcomes, and especially on mortality, to present themselves. Although state Medicaid expansions of the early 2000s have led to substantial decreases in mortality, it remains unknown whether, and how, mortality has been affected by the ACA Medicaid expansion. In this study, we examine its effect on mortality of non-elderly adults, the target expansion population. Given our country’s relentless opioid epidemic, we are particularly interested in the effect of the expansion on drug overdoses.

We exploit the variation in state choices to expand Medicaid under the ACA in a difference-in-differences study design, using Multiple Cause of Death data from the Centers for Disease Control and Prevention. Our baseline specification estimates the effect of the 2014 expansions on county-level mortality rates of non-elderly adults, overall and specifically for drug overdoses. We estimate a linear regression model that includes adjustment for annual county-level demographic composition (sex, race, ethnicity, age group), economic characteristics (median income, poverty rate, unemployment rate), opioid prescription rates (for drug overdose models only), as well as the linear trend and county fixed effects. We find a statistically precise positive relationship between Medicaid expansion and drug overdoses. There are no pre-existing trends for overall drug mortality, opioid mortality, or synthetic opioid mortality. There is no evidence of the expansion’s effect on overall and non-drug related mortality, after three years of expansion. Our findings suggest that Medicaid expansion increases the rate of mortality from drug overdoses, particularly from synthetic opioids, without an offsetting reduction in non-drug related mortality.

We focus on elucidating potential mechanisms that may underlie the observed effects on drug-related and opioid-related mortality. On the one hand, Medicaid expansion may increase access to opioid prescriptions, thus leading to higher opioid dependence prevalence and potentially overdoses. On the other hand, Medicaid expansion seems to increase access to opioid antagonist medication treatment. There is substantive evidence that the expansion increased access to buprenorphine-based treatment for opioid dependence. However, there is also evidence that treatment capacity rates are less than half and treatment receipt rates are one fourth of the rates of opioid abuse or dependence. It is possible that treatment capacity is not sufficient to meet the demand in treatment, especially given the acquired ability to obtain opioid prescriptions among new Medicaid enrollees and associated rise in prevalence. Even though receiving treatment can curtail the epidemic and reduce adverse health consequences, individuals are at a higher risk of overdose death shortly after treatment if they use again, which may be another explanation of our findings. With the opioid epidemic taking increasingly more lives every year, it is essential to understand what may be driving these increases in opioid-related mortality in Medicaid expansion states, especially as more states choose to expand.