Abstract
OBJECTIVE: To measure and compare the scope of US insurers' policies for prior authorization (PA), a process by which insurers assess the necessity of planned medical care, and to quantify differences in PA across insurers, physician specialties, and clinical service categories. DESIGN: Cross sectional analysis. SETTING: PA policies for five insurers serving most of the beneficiaries covered by privately administered Medicare Advantage in the US, 2021, as applied to utilization patterns observed in Medicare Part B. PARTICIPANTS: 30 540 086 beneficiaries in traditional Medicare Part B. MAIN OUTCOME MEASURES: Proportions of government administered traditional Medicare Part B spending and utilization that would have required PA according to Medicare Advantage insurer rules. RESULTS: The insurers required PA for 944 to 2971 of the 14 130 clinical services (median 1899; weighted mean 1429) constituting 17% to 33% of Part B spending (median 28%; weighted mean 23%) and 9% to 41% of Part B utilization (median 22%; weighted mean 18%). 40% of spending ($57bn; £45bn; €53bn) and 48% of service utilization would have required PA by at least one insurer; 12% of spending and 6% of utilization would have required PA by all insurers. 93% of Part B medication spending, or 74% of medication use, would have required PA by at least one Medicare Advantage insurer. For all Medicare Advantage insurers, hematology and oncology drugs represented the largest proportion of PA spending (range 27-34%; median 33%; weighted mean 30%). PA rates varied widely across specialties. CONCLUSION: PA policies varied substantially across private insurers in the US. Despite limited consensus, all insurers required PA extensively, particularly for physician administered medications. These findings indicate substantial differences in coverage policies between government administered and privately administered Medicare. The results may inform ongoing efforts to focus PA more effectively on low value services and reduce administrative burdens for clinicians and patients.