Objectives: Many patients experience difficulty in adhering to medication for both physical and mental health. Our objective was to compare selfreported adherence and electronic monitoring of adherence to oral hypoglycemic agents and antidepressants and to examine the relationship of adherence with clinical outcomes.
Study design: Primary care-based longitudinal study.
Methods: Adherence was assessed in 180 patients prescribed pharmacotherapy for type 2 diabetes mellitus (T2DM) and depression enrolled in a randomized controlled trial of an integrated intervention for depression and T2DM. Adherence data were collected using self report and electronic monitoring. Glycated hemoglobin (A1C) assays were used to measure glycemic control, and the 9-item patient health questionnaire assessed depression.
Results: At 12 weeks, self-reported adherence and electronic monitoring of adherence showed fair agreement (kappa = 0.213, P = .004 for oral hypoglycemic agents and kappa = 0.380, P < .001 for antidepressants). Patients who achieved >80% adherence to oral hypoglycemic agents measured with electronic monitoring were more likely to achieve A1C < 7% compared with patients who did not achieve > 80% adherence at 12 weeks (adjusted odds ratio = 3.52, 95% confidence interval 1.07-11.57). Self-reported adherence to oral hypoglycemic agents was not associated with diabetes outcomes. Measures of adherence for antidepressants were not associated with depression outcomes in models adjusted for potentially influential covariates.
Conclusions: Compared with electronic monitoring of adherence, self-reported adherence tended to overestimate medication adherence. Electronic monitoring of adherence to oral hypoglycemic agents predicted glycemic control, but self-reported adherence did not predict clinical outcomes.