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.