Self-efficacy mediates the associations of diabetes distress and depressive symptoms with type 2 diabetes management and glycemic control.

Background: Adults with type 2 diabetes (T2D) often experience two common diabetes-related psychological distress: diabetes distress and depressive symptoms. Both are associated with adverse diabetes outcomes including poor self-management and glycemic control. However, diabetes distress and depressive symptoms differ in their associations with diabetes outcomes in T2D patients.

Objective: This study proposes a hypothetical model to examine whether self-efficacy mediates the adverse effects of depressive symptoms and/or diabetes distress on self-care behaviors and glycemic control. Additionally, we examined the bi-directional relationships between diabetes distress and depressive symptoms to identify potential underlying mechanisms.

Methods: This study conducted in 15 rural health clinics in Jiangsu province China. 900 adults with T2D participated in the prospective cohort study. The data Diabetes distress (the 17-item Diabetes Distress Scale, DDS17), depressive symptoms(the 10-item Center for Epidemiologic Studies Depression Scale, CESD-10), self-efficacy, self-care behaviors (diet and physical activity), metabolic variables (fasting plasma glucose, FPG) and demographic characteristics were assessed at baseline. Subsequent 12-month Hemoglobin A1C (HbA1c) were measured after baseline. Hierarchical multiple regression and bootstrap mediation analysis were used to test the effects and pathways among these associations.

Results: Of 843 participants (93.67%) of total cohort with available subsequent 12-month HbA1c levels, mean age was 66.08 years and 66.55% were women, 25.15% of them had depressive symptoms (CES-D ≥ 10), 12.20% had moderate diabetes distress (mean DDS ≥2) and 4.98% had the both two psychological distress. Hierarchical multiple regression showed higher DDS score significantly predicted unhealthy diet(β = -1.10, P < 0.001) but not physical activities, while CESD score was negatively associated with physical activity (β = -0.06, P < 0.001) but not diet. No independent effects of the two psychological distress variables on subsequent 12-month HbAc were observed. Mediation analysis supported that elevated self-efficacy solely mediated the negative effect of both diabetes distress and depressive symptoms on diet (DDS score: β = -0.238, 95 BCE% CI [-0.350, -0.141]; CESD score: β = -0.010, 95 BCE% CI [-0.016, -0.005]), physical activities (DDS score: β = -0.446, 95 BCE% CI [-0.630, -0.283]; CESD score: β = -0.019, 95 BCE% CI [-0.030, -0.010]) and subsequent 12-month HbA1c (DDS score: β = 0.105, 95 BCE% CI [0.030,0.189]; CESD score: β = 0.004, 95 BCE% CI [0.001,0.009]) Additionally, the interplay of diabetes distress and depressive symptoms exerts their effects on diabetes outcomes directly and indirectly via self-efficacy.

Conclusions: Self-efficacy may contribute to better diabetes outcomes and ameliorate negative effects of diabetes distress and depressive symptoms.