Association of Drug Rebates and Competition With Out-of-Pocket Coinsurance in Medicare Part D, 2014 to 2018

Key Points Question Is the out-of-pocket burden higher in more competitive drug classes when drug rebates do not reach patients at the point of sale? Findings In this cohort study of 3322 unique National Drug Codes, mean drug list prices were 34% to 61% higher than mean net prices. For a hypothetical consumer paying standard Part D coinsurance on list prices, 2018 out-of-pocket share was 64% in the initial coverage phase, 13% in the catastrophic phase, and greater than 90% in the coverage gap; the patient share was higher for more competitive drug classes. Meaning These findings suggest that the current rebate system places additional burden on patients exposed to list price–based coinsurance, particularly in competitive classes.