Depression is linked to hyperglycaemia via suboptimal diabetes self-management: A cross-sectional mediation analysis

Objective: To analyse if the association between depressive symptoms and hyperglycaemia is mediated by diabetes self-management.
Methods: 430 people with diabetes (57.7% type 1, 42.3% type 2) were cross-sectionally assessed using validated self-report scales for depressive symptoms (Center for Epidemiologic Studies Depression Scale (CES-D)) and diabetes self-management (Diabetes Self-Management Questionnaire (DSMQ)); HbA1c was analysed simultaneously in a central laboratory. Structural equation modelling was used to test if the association between depressive symptoms and hyperglycaemia (HbA1c) was mediated by suboptimal self-management in people with type 1 and type 2 diabetes.
Results: The hypothesised model of depressive symptoms, diabetes self-management and hyperglycaemia fit the data well for both diabetes types (SRMR ≤ 0.04, TLI ≥ 0.99, CFI > 0.99, RMSEA ≤ 0.02 for both models). In both the type 1 and type 2 diabetes group, higher depressive symptoms were associated with lower self-management (P < 0.001) and lower self-management was associated with higher HbA1c (P < 0.001). Results indicated that the association between depressive symptoms and hyperglycaemia was significantly mediated by suboptimal diabetes self-management in both type 1 and type 2 diabetes patients (P < 0.001). Significant direct associations between depressive symptoms and hyperglycaemia, not mediated by self-management, could not be observed.
Conclusions: This study provides good evidence supporting that depression is linked to hyperglycaemia via suboptimal diabetes self-management in both major diabetes types.