Depression and Glycemic Control in a Sample of Patients with Type 2 Diabetes

Abstract

Background: Diabetes mellitus is a serious public health burden, accounting for substantial morbidity, disability, mortality, and health care cost. in addition to impaired physical health, patients with diabetes frequently have comorbid affective illness [1]. People with diabetes are twice likely to be depressed as people without chronic diseases [2], depression may be a risk factor for poor metabolic control in diabetes, however some investigators have found moderate to strong association between depression and glycemic control, although others have found no relationship [3]. Purpose of the study: The purpose of this study was to investigate the association of comorbid depression and glycemic control in a clinical sample of adult Saudi patients with type 2 diabetes. Methods: The sample included 180 type 2 diabetes mellitus adult patients regularly followed in diabetes clinic at Saudi airlines medical center in Jeddah, western Saudi Arabia. We assessed depression by beck depression inventory II (BDI-II), and clinical diagnosis according to DSM IV TR by an expert psychiatrist, and assessed diabetic control by heamoglobin A1c (HbA1c), and fasting blood glucose (FBG). The association between depression and diabetic control was analyzed cross-sectionally, and controlled for demographics (age, sex, employment, education), and clinical variables (smoking, BMI, duration of DM, diabetes medications, medical comorbidities, lipid profile, and renal functions). We used student T test for group comparison, X2 for baseline association between categorical baseline variables, one-way analyses of variant (ANOVA), Pearson correlation coeffecient to examine univariate associations between contaneous baseline variables, and multiple regression analyses to adjust for the demographic and clinical potential confounding factors. Results: Unadjusted analyses revealed a significant positive relationship between BDI scores and HbA1c (r = 0.17, p = 0.02), This relationship was evident throughout the entire range of BDI scores. Also the comparison between clinically depressed group and non-depressed group of patients using T test revealed that HbA1c, is significantly higher in the depressed group with P value (0.01). After adjusment for demographic variables, BDI scores, and clinical depression remained associated with HbA1c changes, but after full adjustment for all demographic and clinical variables, fully adjusted analyses revealed that duration of diabetic illness is the strongest factor which predicts higher HbA1c (p = 0.00), and only clinically diagnosed major depressive disorder (MDD) - but not other depressive diagnoses, and probable severe depression (BDI score >25) - but not the entire range of BDI scores - was less significant predictors of higher HbA1c (P = 0.034 and 0.046 respectively). Conclusion: Patients with diabetes and comorbid sever depressive symptomatology or clinical major depressive disorder are associated with poor glycemic control in type 2 diabetes. However, to study the persistence of this relation prospectively, to explore the factors that could mediate this relation, as well as the study of impact of treating depression on glycemic control may be an interesting areas for further research.