(1083) Examination of the Use of Fixed-ratio insulin/glp-1ra Combination Therapies versus Separate Insulin and GLP-1RA Treatments Among Medicare Beneficiaries

Objectives: Our primary objective is to analyze utilization patterns of fixed-ratio insulin/glucagon-like peptide-1 receptor agonists (GLP-1RA) combination products versus individual products to determine factors which lead to disproportionate use of one versus the other. Secondarily, we will evaluate
potential cost-savings for those patients eligible to convert from individual to combination products. We will also compare copay data of patients who stop GLP-1RAs midyear vs those who continue them for the whole study period to determine if cost was a factor in discontinuation.
In 2022, new federal legislation was introduced that capped the monthly cost of insulin at $35 for Medicare recipients, which is estimated to save approximately 1.6M patients an average of $500 per year. This legislation exclusively addresses the pricing of insulin, without any impact on the pricing of other antihyperglycemic medications. Consequently, certain antidiabetic medications may still be unaffordable for some patients. 
As type 2 diabetes mellitus is a progressive disease, many patients on insulin will eventually need additional pharmacotherapy to maintain glycemic control. According to American Diabetes Association (ADA) Standards of Care guideline, GLP-1RAs are preferred options for pharmacotherapy
intensification and have been shown to provide superior glycemic control when added to basal insulin regimens compared to basal insulin titration alone. However, these agents can be extremely expensive, even after insurance. GLP-1RA copays for Medicare beneficiaries can be nearly $120 per month.
While the branded single drug antihyperglycemic medications preferred by the guideline remain costly, fixed-ratio combination insulin/GLP-1RA products fall under the insulin price cap. Currently, glargine/lixisenatide and degludac/liraglutide combination products are available in the United States and have been shown to provide non-inferior HbA1C reduction compared to premixed insulin and basal-bolus regimens, respectively. Combining insulin and GLP-1RAs may make it possible for more patients to access both medications, as recommended by ADA guideline.
Currently, no identified studies have been completed to analyze how many and which patients are taking advantage of these combination
products.

Methods: This is a retrospective, observational cohort study of prescription fill data for basal insulins, GLP-1RAs, and insulin/GLP-1RA combination products filled between January 1 st through December 31st, 2022, inclusive, across one regional division of a large community-based pharmacy chain, including Kansas, Nebraska, and Missouri. Patients included were 65 years of age or older with Medicare Part D, on metformin, and filled both a basal insulin and a GLP-1RA, including combination products, between January 1st and March 31st, 2022. We excluded patients who do not meet adherence criteria (≥80% proportion days covered).
Data extracted will include fill data of the specified antidiabetic medications as well as patient demographics, including age, gender, prescription insurance coverage, copay information, and zip code. Eligibility for combination products is defined as patients who are using any basal insulin below the maximum deliverable dose of the combination products (60 units for glargine/lixisenatide; 50 units for degludec/liraglutide), and any GLP-1RA at any dose.
Binomial logistic regression will be used to evaluate factors which impact utilization of combination versus individual products. Descriptive statistics will be used to identify the proportion of patients using individual products who may be eligible to switch to combination products. Mean and
standard deviation will be used to assess potential monthly cost-savings of switching from individual to combination products. Comparison of copay data for patients who stop GLP-1RA midyear versus those who continue for whole period examined will determine if cost may be a factor in discontinuation.
All analyses will be conducted using SPSS v. 27 and an a-priori alpha of 0.05. This study is under
IRB review.

Results: Research in progress

Conclusions: Research in progress