Relationship of depression and diabetes self-care, medication adherence, and preventive care

OBJECTIVE - We assessed whether diabetes self-care, medication adherence, and use of preventive services were associated with depressive illness. RESEARCH DESIGN AND METHODS - In a large health maintenance organization, 4,463 patients with diabetes completed a questionnaire assessing self-care, diabetes monitoring, and depression. Automated diagnostic, laboratory, and pharmacy data were used to assess glycemic control, medication adherence, and preventive services. RESULTS - This predominantly type 2 diabetic population had a mean HbA(1c) level of 7.8 +/- 1.6%. Three-quarters of the patients received hypoglycemic agents (oral or insulin) and reported at least weekly self-monitoring of glucose and foot checks. The mean number of HbA(1c) tests was 2.2 +/- 1.3 per year and was only slightly higher among patients with poorly controlled diabetes. Almost one-half (48.9%) had a BMI >30 kg/m(2), and 47.8% of patients exercised once a week or less. Pharmacy refill data showed a 19.5% nonadherence rate to oral hypoglycemic medicines (mean 67.4 +/- 74.1 days) in the prior year. Major depression was associated with less physical activity, unhealthy diet, and lower adherence to oral hypoglycemic, antihypertensive, and lipid-lowering medications. In contrast, preventive care of diabetes, including home-glucose tests, foot checks, screening for microalbuminuria, and retinopathy was similar among depressed and nondepressed patients. CONCLUSIONS - In a primary care population, diabetes self-care was suboptimal across a continuum from home-based activities, such as healthy eating, exercise, and medication adherence, to use of preventive care. Major depression was mainly associated with patient-initiated behaviors that are difficult to maintain (e.g., exercise, diet, medication adherence) but not with preventive services for diabetes.