A new study by researchers at the UW School of Medicine and Public Health and the USC Schaeffer Center for Health Policy and Economics found that the Inflation Reduction Act’s $35 cap on out-of-pocket costs for insulin led to increases in the total number of filled insulin prescriptions for Medicare beneficiaries, according to a recent press release.
Following the cap’s enactment in January 2023, the number of insulin fills among Medicare Part D enrollees increased from 519,588 to 523,564 per month. In contrast, insulin fills decreased among older adults not yet eligible for Medicare during the same period.
The study was published today in the Journal of the American Medical Association. To examine the cap’s effectiveness, researchers used data from IQVIA’s National Prescription Audit, which includes 92% of retail pharmacies and 70% of mail-order and long-term care facility pharmacies in the nation. The study sample included 14 million insulin fills.
Researchers compared changes in insulin fills for Medicare Part D enrollees aged 65–74 with changes among 60- to 64-year-olds without Medicare insurance. The study was designed using a well-established health policy research technique that compares trends between one group exposed to a policy change and another that is not.
The researchers compared outcomes before the Inflation Reduction Act took effect, from September through December 2022, and after, from January through April 2023.
While insulin fills increased among Medicare Part D enrollees after the cap, the number of fills for those without Medicare dropped from 344,719 to 330,229 per month during the same period.
Additionally, the average number of monthly fills with out-of-pocket expenses less than or equal to $35 grew from 340,509 to 366,928 for Medicare enrollees. For those without Medicare, those less expensive fills fell from 242,733 to 220,867, the study found.
After adjusting for differences in the study sample, the analysis suggests that Medicare beneficiaries filled about 50,000 more insulin prescriptions per month that were below $35, and about 20,000 of these fills would not have taken place if not for the policy.
