Impact of IRA Insulin Cap on Rates of Persistence to Basal Insulin
A conversation with Razanne Oueini, PharmD, MSc, CPHQ, senior manager of Performance Measurement at PQA, at PQA 2025.
The Pharmacy Quality Alliance (PQA) developed the Persistence to Basal Insulin (PST-INS) measure through its systematic, consensus-based process, beginning in 2018. Endorsed in 2021, the measure has since been adopted in the Medicare Part D program and included in patient safety reports and the Medicare Part D display page for 2024 and 2025. It assesses the percentage of individuals aged 18 or older who remained persistent with basal insulin therapy over a measurement year.
The measurement is based on a 2014 methodology validated by PQA and is associated with improved outcomes, including lower hemoglobin A1c levels, fewer hospitalizations, reduced readmissions, and fewer emergency department visits.
In 2023, out-of-pocket costs for insulin were capped at $35 for Medicare Part D enrollees under the Inflation Reduction Act, with a similar cap taking effect in July 2023 for Medicare Part B enrollees. In an effort to compare rates of persistence to basal insulin before and after implementation of the cost cap, PQA partnered with Inovalon and used the PTS-INS measurement at the population level.
At the Pharmacy Quality Alliance (PQA) 2025 Annual Meeting, held May 19 to 21 in Tampa, Florida, Drug Topics® sat down with Razanne Oueini, PharmD, MSc, CPHQ, senior manager of Performance Measurement at PQA, to discuss the PTS-INS measurement, how the rates of persistence to basal insulin were impacted after the IRA monthly cap, and how future drug pricing reforms or caps might impact pharmacist-led care and medication management strategies for chronic conditions.
“Based on what we found within our analysis, which showed really a promising association between capping out of pocket costs and improved persistence for patients for their insulin therapy, we would hope that potentially similar caps or other controls on patients out of pocket costs might similarly lead to improved patient adherence or persistence to their therapy,” Oueini said. “We're continuing to monitor that policy landscape as well to see how other types of policies might also lead to better use of medications by patients.”
