Abstract
AIMS: To compare rates of use and adherence for newer versus older second-line diabetes drug classes in commercially insured, Medicare Advantage and dual-eligible (covered by both Medicare and Medicaid) patients. MATERIALS AND METHODS: Longitudinal cohort study using insurance claims data from 1/1/2012 to 12/31/2016 to identify patients with a first prescription, after metformin, of a second-line diabetes drug (eg sulphonylurea, DPP-4 inhibitor, thiazolidinedione, SGLT-2 inhibitor or GLP-1 receptor agonist) and to estimate their adherence to that drug class. Univariate analysis and multivariable logistic regression were used to examine the association between insurance type and use of each drug class, and between insurance type and adherence to each drug class. RESULTS: The study population included 96,663 patients. Trends in drug use differed by insurance type. For example, sulphonylurea use declined among the commercially insured (from 46% to 39%, p < .001) but not among Medicare Advantage or dual-eligible patients. Patterns of adherence also differed between insurance groups. For example, compared to commercial insurance, Medicare Advantage was associated with higher adherence to sulphonylurea (odds ratio [OR] 1.32, 95% CI 1.21-1.43)) but lower adherence to SGLT-2 inhibitors (OR 0.43 (95% CI 0.33-0.56)). CONCLUSIONS: This study finds differences in utilization and adherence for diabetes drugs across insurance types. Older medications such as sulphonylureas appear to be more used and better adhered to among Medicare Advantage recipients, while the opposite is true for newer medication classes. These findings suggest a need to personalize selection of diabetes drugs according to insurance status, particularly when adherence needs optimization.