Three Sides to the Story: Adherence Trajectories During the First Year of SGLT2 Inhibitor Therapy Among Medicare Beneficiaries

Objective: We aimed to understand the factors associated with sodium-glucose cotransporter 2 inhibitor (SGLT2i) adherence and longitudinal adherence trajectories in older adults with type 2 diabetes.

Research Design And Methods: Using Medicare claims data (April 2013-December 2017), we identified 83,675 new SGLT2i users ≥66 years old with type 2 diabetes. We measured SGLT2i adherence as the proportion of days covered (PDC) during the first year of SGLT2i therapy. We used linear regression to assess the association between baseline covariates and PDC. Then we used group-based trajectory modeling to identify distinct longitudinal SGLT2i adherence groups and used a multivariable logistic regression model to examine the association between baseline covariates and membership in these adherence groups.

Results: Unadjusted mean PDC was 63%. Previous adherence to statins had the strongest positive association with PDC (regression coefficient 6.00% [95% CI 5.50, 6.50]), whereas female sex (-5.51% [-6.02, -5.00]), and Black race/ethnicity (-5.06% [-6.03, -4.09]) had the strongest negative association. We identified three adherence trajectory groups: low (23% of patients, mean PDC 17%), moderate (32%, mean PDC 50%), and high (45%, mean PDC 96%) adherence. More patients in the high adherence group were previously adherent to statins (odds ratio 1.43 [95% CI 1.39, 1.48]), and more women (1.28 [1.23, 1.32]) and Black patients (1.31 [1.23, 1.40]) were in the low adherence group.

Conclusions: In a large population of older patients with type 2 diabetes, 45% were highly adherent during the first year of SGLT2i treatment. Female sex and Black race/ethnicity were most strongly associated with low adherence.