Impact of Medicaid Expansions on Opioid Related Mortality and Hospital Visits

In 2015, about as many Americans died from drug poisoning involving opioid analgesics or heroin as from motor vehicle-related injuries. Between 2013 and 2015, the rate of deaths from opioid overdose increased by almost 40% from 5.1 to 7.0 per 100,000 while the rate of deaths involving heroin grew by more than 50% from 2.7 to 4.1 per 100,000.⁽¹⁾⁽²⁾

In 2015, Medicaid covered 3 in 10 people with opioid addiction and thus plays an important and growing role in addressing the epidemic. "Medicaid facilitates access to a number of addiction treatment services, including medications delivered as part of medication-assisted treatment, and it allows many people with opioid addiction to obtain treatment for other health conditions." ⁽³⁾ The expansion of eligibility for Medicaid coverage by many states as part of the implementation of the Affordable Care Act in 2014 made addiction treatment more affordable for previously uninsured low-income individuals. Absent any change in behavior on the part of Medicaid enrollees, greater availability of treatment for opioid use disorder would therefore be expected to curb the growth in the frequency of inpatient and emergency department visits and the death rate due to opioid drug overdose.

At the same time, the Medicaid expansions may have made it easier and cheaper for previously uninsured individuals to access not just addiction treatment medication, such as buprenorphine, but also to prescription opioids that trigger and sustain the addiction in the first place. By improving access to prescription opioids, to addiction treatment, and to more comprehensive care for co-morbid conditions associated with the addiction, it is possible that the Medicaid expansions reduced the cost of opioid addiction borne by individuals who became eligible for Medicaid coverage. A reduction in the addiction's cost would be expected to erode the deterrent effect of the addiction's harmful health effects and thus increase the frequency of inpatient and emergency department (ED) visits and the death rate due to opioid drug overdose.

We compute difference-in-difference estimators to study the effect of Medicaid expansion on opioid-related mortality and hospital visits. We use the National Vital Statistics System to track mortality, and Healthcare Cost and Utilization Project (HCUP) to track ED and inpatient visits from 2007-2015. Deaths per 100,000 population due to Synthetic opioid overdose increased faster in expansion states than in non-expansion states. This effect is only found in expansion states east of the Mississippi river, where synthetic opioids are a closer substitute for heroin than west of the Mississippi river . We also show that deaths from heroin overdoses were increasing faster in these states than in non-expansion states well before the policy was implemented. This pattern is consistent with the hypothesis that the Medicaid expansions may have accelerated the overuse of synthetic drugs where these drugs are close substitutes for heroin. Opioid related ED and inpatient visits also increased faster in the expansion states than in the non-expansion states.