Budget Impact of Eliminating Medicaid Prior Authorizations for Antiretrovirals in Washington State

Background In 2023, Washington state Medicaid eliminated prior authorizations (PAs) for antiretrovirals (ARVs). We estimated the budget impact of this policy change on Medicaid ARV expenditures, 2023 to 2027. Methods Models used 2022 net drug costs reflecting costs minus rebates. Our base case preexposure prophylaxis (PrEP) model assumed changes in the proportions of PrEP users on tenofovir disoproxil fumarate/emtricitabine (TDF/FTC), tenofovir alafenamide/emtricitabine (TAF/FTC), and cabotegravir (CAB) based on 2021–2022 data (before elimination of PAs). We compared base case costs to models assuming changes in PrEP prescribing observed in 2022 to 2023 (first year after elimination of PAs) and models assuming an accelerated increase in TAF/FTC and CAB use. For HIV treatment, models assuming ARV changes based on 2021 to 2022 data (Base Model), changes based on data from 2022 to 2023 (No PA—Stable Increase), and a model based on 2022 to 2023 data but with a declining rate of change in the adoption of bictegravir/TAF/FTC and CAB/rilpivirine (No PA—Declining Increase). We estimated the number of persons with HIV who might be housed using money required to meet new ARV costs using 2023 local Ryan White Program costs for emergency or temporary housing. Results Elimination of PAs will increase Medicaid expenditures for ARVs by an estimated $109.9 to $157.7 million over 5 years. This cost would pay for 5 years of housing for approximately 820 to 1177 people, or 61% to 88% of unstably housed persons with HIV in Washington state. Conclusions Elimination of Medicaid PAs will result in substantial new costs. Changes in drug formulary policy should consider opportunity costs.