Gonzalez JS et al. (2007) Depression, self-care, and medication adherence in type 2 diabetes: relationships across the full range of symptom severity. Diabetes Care [doi:10.2337/dc07-0158]

Growing evidence suggests that depression negatively affects adherence to self-care behaviors (e.g. diet control, exercise, and administration of medication) in patients with type 2 diabetes. Gonzalez and colleagues aimed to characterize the effects of varying severity of depressive symptoms on self-care practices in these patients.

This statistical analysis included 879 of 909 enrolled patients with type 2 diabetes. Depression symptoms were assessed using the Harvard Department of Psychiatry/National Depression Screening Day Scale (HANDS, scale 0–30), with a score ≥9 representing probable major depression over the previous 2 weeks. Self-care adherence was measured with the Summary of Diabetes Self-Care Activities (SDSCA) Questionnaire, which assesses 7-day performance in five domains (diet, exercise, blood glucose monitoring, foot care and medication adherence).

Probable major depression was recorded in 19.3% of patients, and 66.5% of patients showed some depressive symptoms (HANDS score 1–8). Major depression was associated with a significant decrease in adherence to diet, exercise schedule and blood glucose monitoring; patients with probable major depression were also 2.31 times more likely to miss a medication than the other participants (P <0.001). Furthermore, in patients with some depressive symptoms (but not major depression), increasing symptom severity was associated with a significant incremental increase in non-adherence with diet, exercise and medication regimens.

The authors conclude that poor adherence to self-care behaviors is associated with minor depressive symptoms—not just in cases of major clinical depression. Treatment of these minor symptoms might considerably improve self-care of diabetes.