The two groups of states had similar demographic and economic conditions, except that the above-median misuse states had smaller populations and a larger proportion of white residents.
Of note, the patterns of HCV infection mirrored those of heroin overdoses. There was small relative increase in HCV infection rates in 2010 in the above-median OxyContin misuse states, and the gap between above- and below-median misuse states widened more rapidly from 2011 to 2013. “This striking inflection point in the trend of hepatitis C infections for high-misuse states after 2010 mimics the inflection in heroin overdoses that occurred as a result of the reformulation,” they said, noting that heroin morality per 100,000 population was nearly identical in the two groups of states in the pre-reformulation period (0.859 and 0.847).
The falsification exercise looking at nonmedical use of pain relievers other than OxyContin in the two groups of states showed that after 2010 groups’ rates of hepatitis C infections grew at virtually identical rates.
“Thus, the differential risk in hepatitis C infections was uniquely associated with OxyContin misuse, rather than prescription pain reliever misuse more generally,” they said. “This suggests that it was the OxyContin reformulation, not other policies broadly affecting opioids, that drove much of the differential growth.”
The investigators controlled for numerous other factors, including opioid policies that might have an impact on OxyContin and heroin use, prescription drug monitoring programs and pain clinic regulations, as well as the role of major pill-mill crackdowns in 2010 and 2011.
The findings represent a “substantial public health concern,” they said, explaining that, while “considerable policy attention is being given to managing the opioid epidemic ... a ‘silent epidemic’ of hepatitis C has emerged as a result of a transition in the mode of administration toward injection drug use.”
In 2017, the CDC reported on this link between the opioid epidemic and rising HCV infection rates, as well.
Dr. Powell and his colleagues wrote.
Their findings regarding the unintended consequences of the OxyContin reformulation suggest that caution is warranted with respect to future interventions that limit the supply of abusable prescription opioids, they said, adding that “such interventions must be paired with polices that alleviate the harms associated with switching to illicit drugs, such as improved access to substance use disorder treatment and increased efforts aimed at identifying and treating diseases associated with injection drug use.”
However, policy makers and medical professionals also must recognize that reducing opioid-related mortality and increasing access to drug treatment might not be sufficient to fully address all of the public health consequences associated with the opioid crisis. As additional reformulations of opioids are promoted and more policies seek to limit access to prescription opioids, “both the medical and the law enforcement communities must recognize the critical transition from prescription opioids to other drugs, particularly those that are injected, and be prepared to consider complementary strategies that can effectively reduce the additional harms from the particular mode of drug use,” they concluded.
The coauthors cited several limitations, including the possibility that true hepatitis C infection rates might have been underestimated in the study.
He and Dr. Pacula received funding from the National Institute on Drug Abuse. Dr. Powell also cited funding from the Rand Alumni Impact Award.
SOURCE: Powell D et al. Health Aff. 2019;38(2):287-94.