A Comparison of Insurance Coverage of Overactive Bladder Medications in the United States

Objectives: To identify trends in insurance coverage for medications used to treat overactive bladder (OAB) in the United States, specifically assessing coverage for recommended medications of trospium, mirabegron and vibegron as compared to medications with possible risk of cognitive dysfunction (oxybutynin and solifenacin).

Methods: Using the 2021 National Association of Insurance Commissioners Market Share Report, the top seven American insurers offering individual and family marketplace medical insurance plans were identified. Publicly-available formulary information was located through insurers’ websites. Medication coverage tiers were accessed from December 2022 through January 2023 for all on-exchange and off-exchange plans. Plans were located in the most populous zip codes within each geographical coverage area according to 2021 U.S. Census data. For all plans, a lower tier coverage represented lower consumer cost. Coverage for the following medications was investigated: oxybutynin instant-release (IR) 5mg, oxybutynin extended-release (ER) 5mg, solifenacin 5mg, trospium IR 20mg, trospium ER 60mg, mirabegron 25mg, and vibegron 75mg. Coverage was also compared between provider non-preferred medications (oxybutynin, solifenacin) and provider preferred medications (trospium, mirabegron, vibegron). Coverage scores (a weighted average of the associated coverage tiers for individual or grouped medication(s)) were generated relative to the number of plans investigated for each state or insurer with a lower coverage score indicating better coverage (range 0.2-1.0).

Results: Medication coverage for 2,780 insurance plans from 41 states representing an estimated 47% market share were evaluated. Overall coverage for the included OAB medications was similar across the United States. Oxybutynin IR had the best medication coverage across insurers while vibegron had the worst (coverage score of 0.2 oxybutynin vs 0.92 vibegron, p < 0.01). In evaluating all plans, provider preferred medications had significantly worse coverage in comparison to provider non-preferred medications (p < 0.001). Variation between insurers was noted in coverage for anticholinergics with greater specificity for the bladder such as solifenacin and trospium and for extended-release formulations. When assessing coverage as related to age of the population, there was a mild positive correlation between worse coverage score by state and a greater percentage of the state’s population over 65 years old (r=0.21). The best coverage for provider-preferred medications was in Washington and Oregon and the worst coverage was in Maine and Wisconsin. Centene had the best overall coverage for the OAB medications collectively and Kaiser Permanente had the best coverage for the provider-preferred medications. There was no significant correlation found between an insurer’s market share and their coverage of provider-preferred medications (r=0.05).

Conclusions: Despite emerging concerns for long-term effects on cognition associated with prolonged anticholinergic use, beta-3 agonists remain in more expensive tiers across all insurers. Standardization across major insurers for OAB medications is lacking with a need for increased transparency.