Does Medicare Enrollment Raise Diabetes Medication Costs?

TOPLINE:

Reaching age 65 years and enrolling in Medicare is associated with a $23 increase in quarterly out-of-pocket costs for type 2 diabetes (T2D) medications. Medication usage decreased by 5.3%, with a notable shift towards more expensive insulin use.

METHODOLOGY:

• Researchers conducted a retrospective cohort study using 2012-2020 prescription drug claims data from the TriNetX Diamond Network.
• A total of 129,997 individuals diagnosed with T2D were included, with claims observed both before and after age 65 years.
• The primary outcome was patient out-of-pocket costs for T2D drugs per quarter, adjusted to 2020 dollars.
• Drugs measured included biguanides (metformin), sulfonylureas, thiazolidinediones, insulin, dipeptidyl peptidase 4 (DPP-4) inhibitors, glucagon-like peptide 1 (GLP-1) receptor agonists, sodium-glucose cotransporter 2 (SGLT-2 inhibitors), amylin analogs, among others.
• Regression discontinuity design was used to examine the outcomes, adjusting for differential linear quarterly time trends, year fixed effects, and utilization composition and intensity.

TAKEAWAY:

• Reaching age 65 years was associated with an increase of $23.04 in mean quarterly out-of-pocket costs for T2D drugs (95% CI, $19.86-$26.22).
• The 95th percentile of out-of-pocket spending increased by $56.36 (95% CI, $51.48-$61.23) after utilization adjustment.
• T2D medication usage decreased by 5.3% at age 65 years, from 3.40 claims per quarter to 3.22 claims per quarter.
• Higher out-of-pockets were associated with insulin use, DPP-4 inhibitors, GLP-1s and SGLT2 inhibitors.

IN PRACTICE:

“Our results have important implications for the provisions of the Inflation Reduction Act, many of which aim to reduce these costs. Reduced patient cost burden will improve adherence and the management of type 2 diabetes, likely leading to reductions in T2D complications,” wrote the authors of the study.

SOURCE:

The study was led by Douglas Barthold, PhD, Jing Li, MA, PhD, and Anirban Basu, MS, PhD, at the Comparative Health Outcomes, Policy, and Economics Institute, School of Pharmacy, University of Washington, Seattle. It was published online in JAMA Network Open.

LIMITATIONS:

The study’s limitations include the possibility that not all claims of an individual were observed, as TriNetX claims data may not capture individuals who leave the healthcare system or have inaccurate or changing diagnoses. Additionally, the data lack individual-level insurance characteristics. The assumption that individuals transition to Medicare at age 65 years may be true for all participants. The study also lacks clinical information regarding the severity of T2D, which could influence medication usage and out-of-pocket costs.

DISCLOSURES:

The study was supported by grants from the National Institute on Aging (NIA) and the University of Washington’s Population Health Initiative, Student Technology Fee program, and Provost’s office. Barthold and Li received grants from the NIA. Basu reported receiving personal fees from Salutis Consulting, LLC, outside the submitted work. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.