BACKGROUND: Older adults with type 2 diabetes (T2D) face increased complications compared to younger counterparts and the challenge of multimorbidity which may result in complex medication burden, high-cost regimens, polypharmacy, and non-adherence.
OBJECTIVES: This study sought to evaluate primary and secondary medication adherence and persistence patterns of newly initiated glucose-lowering medications in older adults with T2D.
METHODS: This retrospective cohort study included adults ≥ 65 years with T2D newly prescribed a dipeptidyl peptidase-4 inhibitor (DPP4i), glucagon-like peptide-1 receptor agonist (GLP-1 RA), sodium-glucose cotransporter-2 inhibitor (SGLT2i), or sulfonylurea (SU) across six healthcare systems between 2014-2021. Medication order and dispensing data were utilized to quantify primary and secondary adherence and early- and late-stage persistence, during 365 days of follow-up. Multivariable logistic regression models determined associations between medication class and adherence adjusting for site, demographics, and clinical characteristics.
RESULTS: Among 109,118 older adults with T2D prescribed study medications, 1-year adherence was 42% for GLP-1 RA, 46% for DPP4i, 52% for SU, and 60% for SGLT2i. Primary adherence was 94% with little variation between classes. Secondary adherence and late-stage persistence among those who filled the first prescription were lowest for GLP-1 RA (60% and 61%) and highest for SGLT2i (81% and 84%). SGLT2i was associated with a higher adjusted odds of primary adherence (odds ratio: 1.14; 95% CI 1.00-1.30) and secondary adherence (odds ratio: 2.41; 95% CI 2.24-2.59) compared with GLP-1 RA. Select demographic and baseline clinical characteristics were associated with differences in adherence and persistence.
CONCLUSIONS: Adherence to glucose-lowering medications in older adults with T2D varies by medication class, clinical characteristics and demographics. To effectively address individual adherence and persistence, it is important to consider factors beyond the branded status of a drug when designing targeted interventions.