Does prior authorization of buprenorphine/naloxone save money or reduce diversion?

Problem: Concerns about cost and diversion have led Medicaid programs in 48 states to place restrictions on buprenorphine/naloxone, a medication used to treat opioid addiction. Some evidence suggests that patients receiving legitimate prescriptions of buprenorphine/naloxone are a significant source of diverted medication and that higher doses of buprenorphine/naloxone contribute to increased diversion. State responses to this concern range from prior authorization requirements for higher than standard doses to lifetime limits on the duration of treatment. To date, no studies have examined the success of these measures in lowering cost and the impact that they may have on dosage and access to treatment for opioid addiction. We examined one initiative implemented by the Massachusetts Medicaid program in 2008 which required prior authorization for doses higher than the recommended 16 mg/day. We focused specifically on how the policy affected medication cost, total cost and dosage. Population: More than 30,0000 Massachusetts Medicaid beneficiaries with a diagnosis of opioid abuse or dependence between 2003 and 2010.

Methods: We used Medicaid claims, enrollment and encounter data linked with information on other publicly funded substance abuse treatment to identify individuals with an opioid addiction diagnosis who received buprenorphine/naloxone treatment. We calculated the impact of the prior authorization requirement on buprenorphine/naloxone costs, average medical expenditures per person, use of higher than recommended doses and relapse rates. Relapses were defined as a hospital admission, emergency department visit or detoxification with a primary diagnosis of a substance use disorder.

Results: Results indicate significant reductions in the percentage of patients using doses greater than 24 mg/day, from 21.6% to 4.1%. Savings in buprenorphine/naloxone costs were meager, about $79 per patient per year. Relapse rates increased temporarily during implementation of the prior authorization requirement but returned to pre-intervention levels within 6 months. Average medical expenditures did not change significantly.

Conclusions: Prior authorization may be a useful tool for reducing higher doses of buprenorphine/naloxone, which may in turn reduce diversion. However, we were unable to measure the direct impact of reduced doses on diversion. There was a short-lived increase in relapses while the policy change was being implemented. The impact of the prior authorization requirement on Medicaid expenditures was minimal, suggesting that reduced dosing was the primary effect of the prior authorization requirement.