Prior Authorization and Association With Delayed or Discontinued Prescription Fills
PURPOSE Prior authorization requirements are increasing but little is known about their effects on access to care. We examined the association of a new prior authorization policy with delayed or discontinued prescription fills for oral anticancer drugs among Medicare Part D beneficiaries. METHODS Using Medicare part D claims data from 2010 to 2020, we studied beneficiaries regularly filling one of 11 oral anticancer drugs, defined as three 30-day fills in 120 days preceding the plan’s prior authorization policy change on that drug and continuously enrolled in the same plan for 120 days before and after the policy change at the start of a new year. The control group consisted of beneficiaries meeting the same utilization criteria, but who were enrolled in plans at the same time that did not implement a prior authorization policy change. The outcomes of interest were discontinuation of the drug within 120 days (analyzed with regression analyses) and time (in days) to next fill after a pr