Relationship between Treatment Outcomes and Depression and Anxiety in Patients with Type 2 Diabetes Considering the Mediating Role of Physical Activity: A Structural Equation Modeling

 Background and purpose: Depression and anxiety affect the outcomes of diabetes treatment, but, it is not yet completely understood how this happens. We used a structural model to assess the relationship between depression and anxiety considering the mediating role of physical activity on treatment adherence and diabetes control. Materials and methods: The present study was conducted using the data of a cohort study in Kerman, Iran. Data was collected using Beck Depression Inventory, Beck Anxiety Inventory, and Global Physical Activity Questionnaire (GPAQ). Fasting blood sugar level and HbA1c levels were also measured. Diabetes was diagnosed based on medical history. Treatment outcomes included adherence to treatment and diabetes control (measured by HbA1c). Data analysis was carried out in Stata V15 applying structural analysis model. Results: Non-adherence to diabetes treatment was seen in 5.7% of the patients and treatment failure occurred in 67.9%. Anxiety and depression levels in the past had a significant positive correlation with HbA1c levels (β= 0.156, P= 0.032); 61% through direct effect (β= 0.096) and 39% through indirect effect via physical activity (β= 0.060). Also, the findings showed a significant positive correlation between non-adherence to treatment and current anxiety and depression levels (β= 0.093, P = 0.001); 96% through direct effect (β= 0.089) and 4% through indirect effect via physical activity (β= 0.003). Conclusion: Despite optimal self-reports of adherence to treatment, about two thirds of people studied had uncontrolled diabetes. Interventions aiming at increasing physical activity can reduce the adverse effects of anxiety and depression on poor glycemic control.