Study Finds Little Evidence of Link Between Opioid Nonformulary Restrictions and Patient Migration

Formulary restrictions are used by health plans to control cost and encourage quality and safety of the necessary prescription utilization. Although there are Medicare payers that think certain agents, like branded oxycodone HCI extended-release tablets (OERs), are on their formularies to attract high-cost members to join the plan, there is little evidence to suggest that an OER nonformulary restriction has a direct effect on patient enrollment behavior.

A study recently published in Journal of Managed Care and Specialty Pharmacy utilized IMS pharmacy and medical claims data from July 1, 2011, to December 31, 2014, to assess the disenrollment rates, patient migration, and healthcare costs among OER users who disenrolled from a national Medicare Advantage Prescription Drug plan (study-MAPD) in the year following OER nonformulary restriction. The study participants were from study-MAPD, at least 18 years old, were chronic OER users with 2 or more OER claims 6 months prior to the nonformulary restriction data, and had continuous activity in pharmacy and medical claims for 6 months before and after the index.

The researchers used 2012 and 2014 pre-restriction/post-restriction as comparison years. All of the groups were then followed up for 6 months after the index, as the year-to-year disenrollment rates of OER patients, the overall plan, costs, and patient characteristics of those who disenrolled were calculated.

On January 1, 2013, a total of eligible 2935 OER users were identified from the study-MAPD population following the nonformulary restrictions on OERs. For the comparison years, in 2012 (pre-restriction) 2245 patients were identified, and in 2014 (post-restriction), 2222 OER patients were identified. Although patient characteristics were similar among the patient groups during the 3 study years, the disenrollment rates of OER uses varied from 12.9% in 2012, 5.55% in 2013, and 14.3% in 2014, while the disenrollment rates for the overall plan were 18.3% in 2012, 7.6% in 2013, and 14.1% in 2014.

“Approximately 40% of OER users who disenrolled from the study-MAPD migrated to plans also imposing a nonformulary restriction on OERs, while about 25% moved to plans with less restrictive OER coverage,” the authors found. “The majority (59.9%) of patients continued OER use irrespective of their disenrollment from the study-MAPD in 2013.”

As for cost, the decrease in per patient per month (PPPM) cost was not significant, $117, among OER patients post-restriction, while the difference-in-difference analysis demonstrated a net post-restriction increase of $124.

“This analysis indicated that, compared with the overall study-MAPD, disproportionate migration with other plans of chronic OER users was not observed after an OER nonformulary restriction was implemented, and no evidence supported the assumption that imposing an OER nonformulary restriction would lead to more severe and/or more costly patients leaving the plan,” the authors concluded.

Although there is minimal evidence demonstrating that OER nonformulary restriction has an effect on patient enrollment behavior or contribute to higher disenrollment, additional studies are needed to analyze the increases in pharmacy and medical costs before and after the OER restriction in nonopioid users to assess its influence in the results.