(CSPOT04) Socioeconomic and demographic groups associated with adherence to antidiabetic medications in individuals with type 2 diabetes: A nationwide cohort study

Background: Adherence to antidiabetic medications for Type 2 Diabetes (T2D) plays an essential role in improving patients’ health. Existing evidence indicates a persistent issue with non-adherence to antidiabetic medications, and identification of sociodemographic differences is crucial for targeting interventions aimed at improving adherence.

Objectives: To identify socioeconomic and demographic factors related to antidiabetic medication adherence and treatment interruption in individuals with T2D.

Methods: Register-based cohort study including 594,918 individuals with T2D living in Sweden who initiated treatment between 2006 and 2022. Exposures were individualized disposable family income, social income support, cohabitation status and area of residence. Covariates such as sex, education, place of birth and healthcare consumption were accounted for via inverse probability of treatment and censoring weighting. Outcomes were antidiabetic medication adherence during the first year after treatment initiation, with high adherence defined as having a PDC>0.8, while moderate, low, and non-adherence as having 0.5 < PDC ≤ 0.8, 0.2 < PDC ≤ 0.5, and PDC ≤ 0.2, respectively, and treatment interruption at 12, and 60 months after treatment initiation.

Results: Low disposable income (adjusted odds ratio [aOR]: 1.17, 95% confidence interval [CI]: 1.14-1.21), social income support (OR: 1.10, CI: 1.05-1.15), living in larger cities (OR: 1.26, CI: 1.23-1.30) and cohabitation (OR: 1.09, CI: 1.07-1.12) were associated with non-adherence, as compared to high adherence. Consistently, a higher risk of treatment interruption was associated with social income support (relative risk ratio (RR) at 12 months: 1.10, CI: 1.06-1.14; relative RR at 60 months 1.02, CI: 1.00-1.05), cohabiting (RR: 1.01, CI: 1.01-1.02; RR: 1.02, CI: 1.02-1.03), living in large cities (RR: 1.13, CI: 1.12-1.14; RR: 1.08, CI: 1.07-1.08), and low income (RR: 1.05, CI: 1.03-1.07; RR: 1.01, CI: 1.00-1.02).

Conclusions: This large population-based cohort study of individuals with T2D showed that lower income levels, receiving social income support, living in larger cities and cohabitation were associated with non-adherence to antidiabetic medications and higher risks of treatment interruption.