OBJECTIVES: Beginning in 2023, the Inflation Reduction Act (IRA) protects Medicare Part D beneficiaries by establishing a $35 cap on a monthly supply of insulin. Some plans starting in 2021 have already implemented the $35 cap. This study aims to examine the population of beneficiaries that will be affected by the new $35 monthly cap mandate. We focused on patient demographics, healthcare utilization, and out-of-pocket costs for patients over 5 years.

METHODS: This study analyzed the 100% Medicare Part D Event claims data (PDE) files from 2018 to 2022. Patients were selected if they had at least one prescription fill for insulin in the calendar year. Demographic and payer information (Medicare Fee for Service and Medicare Advantage) was identified using the Medicare Beneficiary Summary File (MBSF). Descriptive statistics were done for demographic information, enrollees with average monthly payments of greater than $35, less than $35, and no out-of-pocket payments.

RESULTS: In 2022, we identified 3,283,514 beneficiaries with a prescription for insulin having an average monthly out-of-pocket payment of $22. Patients who spent over $35 per month on insulin (n=886,229 or 27%), spent an average of $68 in 2022, which is a decrease from 2018 in both the total number of beneficiaries (n=1,167,975 or 36%) and an average spend of $95. In 2022, only 2% of patients on insulin with low-income subsidy (LIS) had monthly spending greater than $35 compared to 48% of non-LIS patients. White beneficiaries account for 70% of the patients utilizing insulin of which 32% spent on average greater than $35.

CONCLUSIONS: Over 886,000 beneficiaries will be directly affected by the IRA legislation, and it will save them, on average, over $30 per month. Additionally, those who seek to gain from the legislation are disproportionately white and non-LIS, as those with low-income and dual status were already receiving minimal out-of-pocket expenses.