Utility of urinary podocalyxin levels in patients with and without type 2 diabetic nephropathy and its correlation with renal function

TL;DR

This study shows that urinary podocalyxin levels are higher in type 2 diabetic patients with kidney damage and correlate with albuminuria but not with kidney filtration rate.

Contribution

The study introduces urinary podocalyxin as a potential early biomarker for diabetic nephropathy with specific sensitivity and specificity thresholds.

Findings

Urinary podocalyxin levels were higher in diabetic subjects compared to non-diabetic controls.

Podocalyxin positively correlated with the urine albumin-creatinine ratio in diabetic patients.

Podocalyxin showed high sensitivity and moderate specificity in estimating albuminuria and eGFR in diabetic subjects.

Abstract

Podocalyxin is a urinary protein that may serve as a potential indicator for the early detection of diabetic nephropathy. The objectives of this study were to assess urinary podocalyxin levels in patients with and without type 2 diabetic nephropathy and to determine its correlation with renal function.

This cross-sectional analytical study was conducted at a tertiary care teaching hospital in south India for 18 months. Study subjects were divided into four groups: non-diabetics, diabetics without albuminuria, diabetics with microalbuminuria, and diabetics with macroalbuminuria. Urinary albumin was detected by the dipstick method in a spot urine sample for all study subjects. Urinary albumin was quantified by nephelometry. The enzyme-linked immunosorbent assay (ELISA) technique estimated urinary podocalyxin levels in all groups.

Urinary podocalyxin levels were elevated in diabetic subjects compared to the control group. There was a positive correlation between urinary podocalyxin and urine albumin-creatinine ratio (UACR) in diabetic study subjects. No correlation was found between urinary podocalyxin and estimated glomerular filtration rate (eGFR). Urinary podocalyxin showed a sensitivity of 85% and specificity of 64% (at a cut-off value of 275.56 ng/mL) in estimating albuminuria in diabetic subjects. Urinary podocalyxin showed a sensitivity of 89% and specificity of 78% (at a cut-off value of 273.38 ng/mL) in estimating eGFR in diabetic subjects.

Urinary podocalyxin levels were elevated in patients with type 2 diabetic nephropathy. It was positively correlated with the urine albumin-creatinine ratio in diabetic subjects. However, there was no correlation with the estimated glomerular filtration rate.

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