Association for Public Policy Analysis & Management

The opioid epidemic in the US has led to serious effects on public health, including opioid-related overdoses and mortality. Medicaid enrollees may be at greater risk of these outcomes due to their exposure to higher doses of prescription opioids relative to commercially insured individuals. Formulary management tools, such as prior authorization policies, which are widely used in Medicaid for cost-containment, may lower rates of opioid medication abuse and overdose among enrollees. However, little is known about the impact of prior authorization, especially for commonly used short-acting opioids, on public health outcomes. We used variation in the use of prior authorization for opioids across managed care organizations in Medicaid to examine the potential for these tools to reduce opioid abuse and overdose.

We conducted a retrospective cohort study using Pennsylvania Medicaid data from 2010 to 2012. We collected information from Pennsylvania’s Medicaid managed care organizations as well as their fee-for-service program on use of prior authorization for opioid analgesics during our study period. Among patients initiating opioid treatment, we compared rates of opioid abuse and overdose among enrollees in Medicaid plans that utilized prior authorization for a high number of medications (17-74 opioids), a low number of medications (1 opioid), and those in plans not requiring prior authorization for any opioids. We used a generalized estimating equations model with a log link and Poisson distribution to assess the relationship between the presence of prior authorization policies and opioid medication abuse and overdose, as measured in Medicaid claims data, adjusting for demographics, comorbid health conditions, benzodiazepine/muscle relaxant use, and emergency department use.

The study cohort included 297,634 enrollees, with a total of 382,828 opioid treatment episodes. Compared to plans with no prior authorization, enrollees in high prior authorization plans (Adjusted Ratio Rate [ARR]=0.89, 95% CI=0.86-0.93) and low prior authorization plans (ARR=0.93, 95%CI=0.87-0.99) developed opioid abuse diagnoses at lower rates. Enrollees in the low prior authorization plan had a lower rate of experiencing an overdose than those enrolled in plans with no prior authorization (ARR=0.75, 95% CI=0.59-0.95). Enrollees in high prior authorization plans were less likely to experience an overdose but this association was not statistically significant.

Enrollees in Medicaid plans that utilized prior authorization policies appeared to have lower rates of abuse and overdose following initiation of opioid medication treatment than enrollees in plans that did not use these formulary management tools. Medicaid programs and the managed care organizations with which they contract may consider expanding use of these tools as part of a comprehensive strategy to address the opioid abuse and overdose crisis.