Depression, Self-Care, and Medication Adherence in Type 2 Diabetes: Relationships Across the Full Range of Symptom Severity

Abstract

OBJECTIVE -- We examined the association between depression, measured as either a continuous symptom severity score or a clinical disorder variable, with self-care behaviors in type 2 diabetes.

RESEARCH DESIGN AND METHODS -- We surveyed 879 primary care type 2 diabetes patients using the Harvard Department of Psychiatry/National Depression Screening Day Scale (HANDS), the Summary of Diabetes Self-Care Activities (SDSCA), and self-reported medication adherence.

RESULTS -- Nineteen percent of patients met criteria for probable major depression (HANDS ≥ 9) and an additional 66.5% reported at least some depressive symptoms. After controlling for covariates, patients with probable major depression reported significantly fewer adherent days to diet, exercise, and glucose self-monitoring regimens (p-values <0 .01) and a 2.3-fold increased odds of missing medication doses in the previous week (95% CI = 1.5 - 3.6, p < 0.001) compared to all other respondents. Continuous depressive symptom severity scores were better predictors of nonadherence to diet, exercise, and medications than categorically defined probable major depression. Major depression was a better predictor of glucose monitoring. Among the two-thirds of patients not meeting major depression criteria (HANDS < 9, n = 709), increasing HANDS scores were incrementally associated with poorer self-care behaviors (p-values <0 .01).

CONCLUSIONS -- These findings challenge the conceptualization of depression as a categorical risk factor for nonadherence and suggest that even low levels of depressive symptomatology are associated with nonadherence to important aspects of diabetes self-care. Interventions aimed at alleviating depressive symptoms, which are quite common, could result in significant improvements in diabetes self-care.