Correlation of spot urine protein-creatinine ratio with 24-hour urinary protein in type 2 diabetes mellitus patients: a cross sectional study

BACKGROUND: Diabetic nephropathy is the major cause for chronic renal failure (CRF) and proteinuria is an independent risk factor for end stage renal disease. Hence, early identification and quantification of proteinuria is of prime importance in the diagnosis and management. METHODS: This study was conducted amongst 42 diabetic subjects from HSK hospital, Bagalkot. Twenty four-hour urine protein and random urine protein to creatinine ratio (P:C) was determined. Pearson’s correlation, sensitivity, specificity, positive and negative predictive values were determined using 24-hour urinary protein as a gold standard for spot urine P:C ratio. ROC curve and area under curve was also determined using SPSS (11.5) software. All the results were expressed in mean±SD. RESULTS: Forty two diabetes mellitus patients participated in this study. The average of 24 hour urinary protein was 1.6 ± 1.7 gm/day. The spot urine P:C ratio was 1.27 ± 1.55. There was a positive correlation between 24 hours urinary protein and spot urine P:C ratio (r = 0.925, p < 0.0001). The area under the ROC curve for urine P:C ratio at various cutoff was 0.947 (95% confidence interval: 0.831-0.992, p < 0.0001). The sensitivity and specificity was 80.65% and 100% respectively at P:C ratio cutoff of 0.3. CONCLUSIONS: The random urine P:C ratio predicts the amount of 24-hour urinary protein excretion with high accuracy. Hence it can be used as a faster diagnostic substitute for 24-hour urinary protein estimation.