Three Sides to the Story: Adherence Trajectories During the First Year of Sodium–Glucose Cotransporter 2 Inhibitor Therapy Among Medicare Beneficiaries
Design and Methods Using Medicare claims data (April
2013-December 2017), we identified 83,675 new SGLT2i users aged ≥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%), or high adherence (45%, mean PDC 96%). More patients in the high adherence group were previously adherent to statins [OR 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.