Association of Depression with Complications of Type 2 Diabetes – The Chennai Urban Rural Epidemiology Study (CURES- 102)

Abstract

Objective: The aim of the study was to assess the relationship between depression and diabetic complications among urban south Indian type 2 diabetic subjects [T2DM]. Methods: T2DM subjects [n= 847] were recruited from the Chennai Urban Rural Epidemiology Study [CURES], a population based study in Chennai (formerly Madras) in South India. A previously validated depression questionnaire [PHQ-12 item] was administered. Four field stereo retinal colour photography was done and diabetic retinopathy [DR] was classified according to the Early Treatment Diabetic Retinopathy Study grading system. Neuropathy was diagnosed if the vibratory perception threshold of the right great toe, measured by biothesiometry, was ≥20. Nephropathy was diagnosed if urinary albumin excretion was ≥300 mg/mg creatinine. Peripheral vascular disease [PVD] was diagnosed if an ankle-brachial index was <0.9. Coronary artery disease [CAD] was diagnosed based on a past history of documented myocardial infarction and/or electrocardiographic evidence of Q wave and/or ST segment changes. Results: Of the 847 T2DM studied, 198 (23.4%) were found have depression. The prevalence of depression was significantly higher among diabetic subjects with DR (35.0% vs 21.1%,p<0.001), neuropathy (28.4% vs15.9%,p=0.023), nephropathy (35.6% vs 24.5%,p=0.04) and PVD (48.0% vs 27.4%,p<0.001) as compared to subjects without these complications. DR, neuropathy, nephropathy, and PVD were associated with depression even after adjusting for age, gender, duration of diabetes and glycated haemoglobin. DR (Odds ratio [OR] =2.19, Confidence interval [CI]:1.45-3.51,p<0.001) was associated with depression even after adjusting for neuropathy and nephropathy. There was also a significant association between depression and neuropathy, after adjusting for retinopathy and nephropathy (OR=2.07,CI:1.41-3.04,p<0.001). There was a significant association of depression with nephropathy but this was lost (OR=1.71, CI: 0.87-3.35,p=0.119) after adjustment for retinopathy. PVD (OR=3.52,CI:1.94- 6.40,p<0.001) remained significantly associated with depression even after adjusting for CAD. However, there was no significant association of depression with CAD (OR=0.73, CI:0.42 -1.27, p=0.264). Conclusion: Among Asian Indians, the prevalence of depression is higher in T2DM subjects with retinopathy, neuropathy, nephropathy and PVD compared to those without the respective complications.