Psychiatry Research EG

Objectives The aim of this study was to examine the longitudinal effect of depression on glycemic control in a sample of patients with type 2 diabetes. Patients and methods Patients were recruited from the diabetes clinic in Saudi Airlines Medical Centre, Jeddah; the baseline study community consisted from 172 patients with type 2 diabetes. They were assessed for depression using Beck Depression Inventory-II and a diagnostic interview and for diabetic control using HbA1c. We created a person–period dataset for each patient to cover 6-month intervals up to 3 years. We used the generalized estimation equation (GEE) for the analysis of longitudinal data. HbA1c was the response variable, whereas depression and time were the main covariates. Variables were included in GEE models based on clinical importance and preliminary analysis. Other variables included as covariates were sex, education, duration of diabetes, comorbidity, and Low-density Lipoprotein (LDL). All statistical analyses used an α-value of 0.05 as the level of significance and were performed using SPSS software version 21. Results Unadjusted HbA1c means were significantly higher in depressed as against nondepressed individuals at all time points. Adjusted HbA1c means in the final GEE model were significantly higher in depressed as against nondepressed individuals. In all adjusted models, depression was a significant predictor of glycemic control, whether it was measured as the Beck Depression Inventory score (estimate=0.049, P=0.002) or diagnoses ofmajor depressive disorder (estimate=2.038,P=0.000) or other depressive disorders (estimate=1.245, P=0.000). Conclusion This study on a clinical sample of type 2 diabetic patients demonstrates that there is a significant longitudinal relationship between depression and glycemic control and that depression is associated with a persistently higher HbA1c over time. Keywords: depression, depressive disorders, diabetes, diabetic control, hba1c, major depressive disorder, type 2 diabetes