A Study of Association of Urinary Nephrin with Albuminuria in Patients with Diabetic Nephropathy

BACKGROUND AND AIMS: Diabetes mellitus and its complications are associated with high mortality and morbidity. Early detection is mandatory to improve quality of life years in patients with diabetic nephropathy. Hyperglycaemia disrupts podocytes, both structurally and functionally, leading to excretion of nephrin which is present in the glomerular filtration barrier. This study was undertaken to find out whether urinary nephrin is a better indicator of podocyte injury than albuminuria in patients with diabetic nephropathy. METHODS: The study included 125 type 2 diabetes mellitus patients as cases categorized into three groups, depending upon albumin excretion. Age and sex matched 45 individuals without diabetes mellitus were chosen as the control group. The study protocol was approved by Institutional Ethics committee. Microalbumin was estimated by immunoturbidometry and urinary nephrin by ELISA. ANOVA and Tukey post-hoc tests were done to compare the data between the groups. Correlation studies were done. Odds ratio for nephrin was calculated. P value less than 0.05 was considered statistically significant. The statistical analyses were performed with SPSS software version 13.0. RESULTS: The urinary nephrin was found to be proportionately increased from normoalbuminuria to macroalbuminuria and it was statistically significant, with sensitivity of 92.5% and specificity of 76.7%, the cut-off value of urinary nephrin was 97.5ng/mL. CONCLUSION: Albuminuria has been used as an independent predictor of diabetic nephropathy. The statistical significant difference between the groups inferred that urinary nephrin excretion increased even in the stage of normoalbuminuria. Nephrin expression and its phosphorylation get altered by hyperglycaemia, contributing to renal damage. Nephrin was found to be a sensitive marker of early kidney dysfunction in diabetic patients.