Prior Authorization Requirements in Medicare Advantage and County Social Vulnerability.

OBJECTIVE: To assess whether Medicare Advantage (MA) beneficiaries in socially vulnerable counties face more restrictive prior authorization (PA) requirements. STUDY DESIGN: Cross-sectional analysis of 2945 US counties in 2022. METHODS: The primary outcome was the mean percentage of Medicare-covered service categories requiring PA across all MA plans in a county, adjusted for service mix and plan enrollment and derived from the CMS MA benefit, landscape, and enrollment files. Secondary outcomes included county-level PA rates for selected service categories, the number of plans with more vs less restrictive PA policies, and mean monthly premiums. The exposure was the county-level Social Vulnerability Index (SVI) subdomains (socioeconomic status, household characteristics, racial/ethnic minority status, housing and transportation), categorized into deciles. Unadjusted linear regression models were used, weighted by county MA enrollment. RESULTS: Counties in the highest vs lowest SVI decile in the socioeconomic domain had overall PA rates that were 7.2 percentage points (PP) higher ( P  < .001), with the largest gap for psychiatric services (16.9 PP; P  < .001). Conversely, mean monthly premiums declined across socioeconomic deciles, from $29 in the first decile to $8 in the 10th ( P  < .001). Total plan counts were stable across deciles, but the composition differed: The most vulnerable counties offered 5 fewer plans with less restrictive PA policies and 4 more plans with more restrictive policies (both P  < .001). CONCLUSIONS: MA beneficiaries in socially vulnerable counties face more restrictive PA requirements, especially for psychiatric services. These disparities may compound existing structural barriers and warrant consideration in future MA policy reforms.