by Jinghong Chen

About 1 million Medicare Part D beneficiaries without low-income subsidies (LIS) had out-of-pocket prescription drug spending above the catastrophic threshold in 2017, with the average annual OOP cost reaching $3,214, according to a recent Kaiser Family Foundation analysis. As Part D does not place a hard cap on OOP spending, enrollees are required to pay up to 5% of their total drug costs for spending above the catastrophic threshold, unless they receive LIS. Over the past decade, the share of OOP spending in the catastrophic coverage phase has increased among Part D enrollees with high OOP drug costs, from 13% in 2007 to 44% in 2017. The Affordable Care Act’s changes to Part D benefit design, which included a manufacturer discount on brand-name drugs while in the coverage gap, contributed to that growth.

NOTE: “High out-of-pocket drug costs” refers to Part D enrollees without low-income subsidies who incurred drug spending above the catastrophic coverage threshold. Analysis of top 10 drugs is limited to drugs with 100 (500 weighted) or more users in 2017.

SOURCE: Kaiser Family Foundation, “How Many Medicare Part D Enrollees Had High Out-of-Pocket Drug Costs in 2017?” KFF analysis of 2007-2017 prescription drug claims data from the CMS Chronic Conditions Data Warehouse. Visit