Factors associated with antidiabetic medication non-adherence in patients with incident comorbid depression

To identify factors associated with antidiabetic drug (AD) non-adherence among patients with type 2 diabetes and depression.

We conducted a population-based retrospective cohort study among new AD users with a diagnosis of depression following AD initiation. We used public health insurance data from Quebec. The dependent variable was non-adherence (i.e., <90% of days covered by ≥1AD) in the year after a depression diagnosis. Different sociodemographic, clinical and medication-related variables were assessed as potential factors of non-adherence to AD treatment. We performed univariate and multivariate logistic regressions.

We identified 3106 new users of ADs with a diagnosis of depression between 2000 and 2006. Of these individuals, 52% were considered non-adherent to their ADs. Baseline non-adherence, younger age, the addition of another AD to the initial treatment, <4 drug claims, visits with several different physicians, high socioeconomic status, and a small number of diabetes complications were associated with AD non-adherence.

The factors identified in the present study may help clinicians recognize patients with type 2 diabetes and incident depression at increased risk for non-adherence. In these patients, close follow-up and targeted interventions could help improve adherence to AD treatment, improve glycemic control and reduce complications.