Relationship Between Depression Scores And Poor Glycemic Control In Type 2 Diabetes

Abstract

Background: Depression and diabetes frequently coexist, forming a bidirectional relationship that worsens metabolic outcomes and quality of life. Poor glycemic control among patients with type 2 diabetes mellitus (T2DM) is often influenced by psychological distress, reduced medication adherence, and unhealthy lifestyle behaviors. Understanding this association is critical for developing integrated care models that address both metabolic and mental health needs. Objective: This study aimed to evaluate the association between depression severity and glycated hemoglobin (HbA1c) levels in patients with T2DM, while examining medication adherence, clinic attendance, and lifestyle behaviors as potential mediators of this relationship. Methods: A cross-sectional study was conducted over eight months among 240 adults with T2DM attending tertiary hospitals in Lahore, Pakistan. Depression severity was assessed using the Patient Health Questionnaire-9 (PHQ-9), medication adherence with the Morisky Medication Adherence Scale (MMAS-8), and lifestyle behaviors with the Summary of Diabetes Self-Care Activities (SDSCA). Clinical data, including HbA1c levels, were obtained from medical records. Pearson correlation and multiple linear regression analyses were performed to identify predictors of glycemic control, assuming normal data distribution. Ethical approval was obtained from the Institutional Review Board of the relevant institute. Results: The mean HbA1c was 8.3 ± 1.4%, and mean PHQ-9 score was 10.2 ± 5.3. Depression scores were significantly correlated with HbA1c (r = 0.41, p < 0.001). Medication adherence (r = -0.36, p < 0.001) and lifestyle behaviors (r = -0.32, p < 0.001) were inversely associated with HbA1c. Regression analysis identified depression (β = 0.38, p < 0.001), medication adherence (β = -0.25, p < 0.001), and lifestyle behaviors (β = -0.22, p = 0.003) as independent predictors of HbA1c. Medication adherence partially mediated the depression–HbA1c relationship. Conclusion: Depression significantly contributes to poor glycemic control in T2DM, partly through its adverse effects on adherence and self-care. Integrating mental health screening into diabetes management may enhance both psychological and metabolic outcomes.