Q&A: Insulin Cost Cap Linked to Better Treatment Persistence | PQA 2025
Razanne Oueini, PharmD, MSc, CPHQ, discusses how rates of persistence to basal insulin were impacted after the IRA monthly cap.
The Pharmacy Quality Alliance (PQA) developed the Persistence to Basal Insulin (PST-INS) measure to track patients who maintain consistent basal insulin use over a year. Endorsed in 2021, it is now used in Medicare Part D performance and safety evaluations. The measure, based on a 2014 validated methodology, is linked to better outcomes like lower A1c, fewer hospitalizations, and reduced ER visits.
Q&A: Insulin Cost Cap Linked to Better Treatment Persistence | PQA 2025 / Pixel-Shot - stock.adobe.com
In 2023, insulin costs were capped at $35 for Medicare enrollees under the Inflation Reduction Act. To assess the impact, PQA partnered with Inovalon to evaluate persistence rates using PST-INS before and after the cap’s implementation.
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.
READ MORE: Impact of IRA Insulin Cap on Rates of Persistence to Basal Insulin
Drug Topics: Can you discuss the Persistence to Basal Insulin (PST-INS) health plan performance measure?
Razanne Oueini, PharmD, MSc, CPHQ: PQA developed a persistence to basal insulin measure, which is a health plan performance measure that was developed through PQA’s systematic and consensus based process in 2018 and was endorsed in 2021. Since then, that measure has been used within the Medicare Part D program. It quickly moved into the patient safety reports, and as of 2024 has been on the Medicare Part D display page.
The measure looks at the percentage of individuals who are 18 years or older who were treatment persistent to their basal insulin therapy within a measurement year. It utilizes a bit of a complex methodology that was first published by a group back in 2014 and was since validated by a PQA internal study. Since then, the performance on the measure and persistence to insulin therapy as defined by the measure has been linked to a lot of positive health and economic outcomes, things like reduced hemoglobin A1c fewer, hospitalizations and readmissions, and fewer emergency department visits. The measure has been linked to these great outcomes, which we of course are always hoping a quality measure is going to lead to.
Drug Topics: How were the rates of persistence to basal insulin impacted after the IRA’s monthly cost cap was implemented?
Oueini: Within our study, we compared rates of persistence to basal insulin in the year prior to the implementation of the cost cap. That was 2022 and in the first year of implementation of the out of pocket cap, which was 2023, we saw a statistically significant increase in overall rates of persistence in that first year. Additionally, we were looking at a nationally representative sample of Medicare Advantage patients. That was our population, but we were pleased to see that overall improvement in persistence, as well as when we drilled down to a variety of sub populations, improvements among almost all sub populations that were looked at, which included things like patient sex, recent ethnicity, geographic divisions and others.
We did see even more pronounced improvements in persistence among a couple of those sub populations compared to overall. Those included males, specifically patients of black race and those within certain census divisions where there's a higher prevalence of type 2 diabetes.
Drug Topics: How might future drug pricing reforms or caps impact how patients adhere to medications?
Oueini: 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. 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.
