The following originally appeared on The Upshot (copyright 2017, The New York Times Company) and was jointly authored by Aaron Carroll and Austin Frakt.
The theory has gained such prominence that a United States senator is investigating it.
“Medicaid expansion may be fueling the opioid epidemic in communities across the country,” Senator Ron Johnson, Republican of Wisconsin, wrote recently.
Some conservative opponents of the Affordable Care Act have been passing around the same theory for months. It’s a politically explosive (and convenient) argument, but is it true? Substantial evidence suggests the answer is no, but let’s give it a fair hearing.
Some data seems to support this connection, and the idea has a certain logic. Coverage from Medicaid — or any kind of health insurance for that matter — plays a role in access to prescription opioids, just as it does for access to many other types of health care.
We know from earlier analyses that Medicaid enrollees tend to be prescribed opioids more frequently than people with other kinds of coverage. But that could be because of other factors also related to insurance. It’s important to remember that people who go on Medicaid are sicker than those with other forms of coverage, so they may have more pain that warrants opioids.
It is also true that the 31 states that expanded Medicaid experienced a larger increase in drug overdoses between 2013 and 2015 than states that did not. As Mr. Johnson wrote, “These data appear to point to a larger problem.”
But this is a weak foundation on which to base a conclusion that Medicaid is driving the opioid epidemic. Responding to these facts when they were first noted, a Department of Health and Human Services statement said, “Correlation does not necessarily prove causation, and additional research is required before any conclusions can be made.”
In a post on the Health Affairs blog, Andrew Goodman-Bacon, an economist at Vanderbilt, and Emma Sandoe, a Ph.D. student in health policy and political analysis at Harvard, recommend that, to understand the opioid epidemic and Medicaid’s role better, we should look much further back than 2013.
For example, OxyContin prescriptions for noncancer pain grew by a factor of almost 10 between 1997 and 2002, long before the A.C.A. was signed into law. Drug-related mortality rates doubled between 1999 and 2013, the year before most states expanded Medicaid.
Further, while it is true that drug-related deaths have grown more rapidly in expansion states than in other states, that more rapid growth started in 2010, before the A.C.A. expansion. This suggests that causes other than Medicaid are more likely. Given the timing of these findings, “there is little evidence to support the claim that Medicaid expansion caused the increase in opioid-related deaths,” Ms. Sandoe said.
Yes, Medicaid could still be playing a role, but as with all correlations, it’s important to consider both directions of causality. It’s possible that states experiencing larger growth in drug deaths might have been more eager to expand Medicaid programs. After all, Medicaid also provides financial support for drug abuse treatment. One study found that prescriptions for medications that treat opioid addiction increased by 43 percent in Medicaid expansion states, relative to states that did not expand their programs. When Gov. John Kasich, a Republican, talks about why he’s happy that Ohio expanded the Medicaid program, he often cites the opioid crisis in his state.
Craig Garthwaite, a Republican labor economist of Northwestern University’s Kellogg School of Management, said: “It’s not that there isn’t a single case of an individual insured by Medicaid developing an opioid habit or illicitly obtaining drugs. But the evidence to date doesn’t suggest that this is the net effect.”
Another way to test the Medicaid-opioid connection is to examine a dose response. States with higher levels of uninsurance saw greater coverage gains through Medicaid. If more Medicaid causes more opioid death, then states that added more Medicaid beneficiaries should see greater increases than states with smaller coverage expansions. But Mr. Goodman-Bacon and Ms. Sandoe show that the opposite holds. Counties in states with historically higher levels of uninsurance (and therefore greater subsequent growth in Medicaid) had lower growth in drug-related death rates from 2010 to 2015. This relationship holds within expansion and nonexpansion states separately.
Or course, drug-related deaths include those from prescription opioids as well as those from black-market drugs (like heroin and fentanyl). Medicaid directly enhances access only to the former. This makes it hard to identify the role of Medicaid in the opioid crisis definitively, which is all the more reason to be cautious about suggesting the program is fueling it.
“The really sad thing here is that these numerical arguments have the veneer of seriousness, and as a result, they can drive really bad policy,” Mr. Garthwaite said.
Providing health care through insurance means providing access to both its benefits and harms. No one seems concerned that the increased access to health care that private insurance provides might lead more people to take opioids — only that Medicaid could. It’s also interesting to note that no one makes assertions that increased coverage, even increased Medicaid coverage, probably leads to more deaths by medical errors.
We should not look at harms in isolation. Even if Medicaid does enhance access to prescription opioids, thereby playing a role in their misuse, that is far from the only thing the program does. Medicaid provides many other benefits, about which we’ve written, including increased access to substance use disorder treatment.
To use a theoretical Medicaid-opioid connection (for which the evidence is weak anyway) to justify scaling back Medicaid ignores the larger picture — that it is a crucial aspect of our safety net, providing access to health care and financial protection that many low-income Americans could not otherwise obtain.