Diabetic nephropathy and associated risk factors for renal deterioration

Predominantly diabetic nephropathy starts with glomerulosclerosis, when plasma molecules cross the dismantled glomerular basement membrane (GBM) and subsequently appear in urine. Therefore proteinuria is a sensitive criterion to diagnose progressive renal impairment and the presence of immunoglobulin like large molecules is potentially able to predict severity of nephropathy. Directly, or indirectly hyperglycemia induces proteinuria and high urinary excretion of IgG appears with progression of glomerular injury. This is an observational study of 683 patients with type 2 diabetes mellitus. Patients with varying degree of proteinuria were enrolled and classified into three groups according to the urinary albumin creatinine ratio (UACR, 300 mg/g creatinine.) and each group was further sub-classified into the low and high urinary IgG creatinine ratio (UIgGCR) based on the median value. Biochemical parameters were analyzed by standard laboratory methods. The association of proteinuria and odds ratio for risk factors of diabetic nephropathy was estimated using multinomial logistic regression models. The normoalbuminuric and microalbuminuric patients with high UIgGCR had shown lower eGFR (p < 0.05). There was no interaction observed between higher UIgGCR and lower eGFR in regression model analysis. Multinomial logistic regression model estimated the odds ratio for the AGEs, AOPP, lipid hydroperoxides and lipid peroxidation products were increased; 5.64 (95% CI 3.52–9.04), 1.03 (95% CI 1.02–1.04), 2.71 (95% CI 2.05–3.57) and 13.72 (95% CI 6.98–26.95) respectively with high UIgGCR in diabetic patients. High UIgGCR has shown a significant association with decreased eGFR and increased odds for potential hazardous factors. The current study has shown UIgGCR as an increased relative risk, and threat for rapid progression of diabetic nephropathy, possibly because GBM is the primary vulnerable site for deterioration by several hazardous metabolites. In conclusion, association between fractional clearance of IgG and relative risk of GBM threatening factors should be useful for prediction of progressive nature of diabetic nephropathy.