Evaluation of spot urinary protein creatinine ratio for quantification of proteinuria in women with hypertension in pregnancy: A prospective observational study

Abstract

To calculate the cut off value of the spot urine protein/creatinine ratio (PCR) for predicting significant proteinuria in our population of patients with HTN (hypertension) in pregnancy, and study its correlation with total urine estimation in 24 hour collection of urine. We conducted a prospective observational study among pregnant women with HTN attending Department of Obstetrics and Gynaecology, Lok Nayak Hospital, Maulana Azad Medical College, New Delhi. Two hundred patients with singleton pregnancy with hypertension and gestational age >20 weeks were included in the study. Both 24-hour urine protein measurement and a spot urine PCR was done for every patient. Follow up was performed till delivery and outcomes were noted. Significant proteinuria was found in 64 (32%) patients. The study suggested moderate degree of correlation between spot urine PCR and 24 hour urine protein, with a correlation coefficient of 0.47, p<0.001 (n=200). The correlation coefficient for ambulatory patients was 0.415 whereas it was much higher i.e. 0.776 for nonambulatory patients.The ROC curve analysis revealed an excellent sensitivity of 96.3% and specificity of 84.2% with AUC 0.91 (excellent) for a cut-off value of spot PCR >0.19 to detect significant proteinuria in our population. The negative predictive value was 98.4% and positive predictive value was 69.3%. The spot urine Protein Creatinine ratio can be considered an excellent ruling out test. However, women with abnormally high spot urine PCR should undergo 24-hour urine protein measurement before clinical intervention is done.