Correlation of Spot Urine Protein:Creatinine Ratio with 24-hour Urinary Protein in Preeclampsia: A Cross Sectional Study

Abstract

Aims: The present study was undertaken to evaluate the diagnostic value of protein:creatinine  ratio in spot voided urine sample for detection of proteinuria as compared to those of 24 hour urine sample in patients with preeclampsia, and also to determine the optimal cut-off value of protein:creatinine ratio with best sensitivity and specificity for the prediction of significant proteinuria. Study Design: Cross sectional study. Place and Duration of the Study: The study was conducted at teaching hospital in North Karnatak, India. The study was conducted from Jan 2012 to February 2013. Methods: This study was conducted on 52 preeclampsia patients. The 24 hour urine protein and random urine protein:creatinine ratio was determined. Pearson’s correlation, sensitivity and specificity were determined using 24-hour urinary protein as a gold standard for spot urine protein:creatinine ratio. Receiver operators characteristic (ROC) curve and area under curve was also determined using SPSS (11.5) software. All the results were expressed in mean±SD. Results: Fifty two preeclampsia patients participated in this study. The average 24 hour urinary protein was 1643.3±2079.5 mg/day. The spot urine protein:creatinine ratio was 1.47±1.68. There was a positive correlation between 24 hour urinary protein and spot urine protein:creatinine ratio (r = 0.86, P<0.0001). The area under the receiver operators characteristic curve for urine protein:creatinine ratio at various cut-off was 0.914 (95% confidence interval: 0.800-0.975, P<0.0001). The sensitivity and specificity was 71.5% and 100% respectively at protein:creatinine  ratio cut-off of 0.66. Conclusion: The random urine protein:creatinine  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 in preeclampsia.