Spot Urine Protein-to-Creatinine Ratio to Predict the Magnitude of 24-Hour Total Proteinuria in Preeclampsia of Varying Severity.

OBJECTIVE: The predictive value of spot urine protein-to-creatinine ratio (PCR) for estimating total 24-hour proteinuria in severe preeclampsia is unclear. This study aimed to assess the diagnostic accuracy of spot urine PCR for ascertaining the magnitude of proteinuria in women with preeclampsia of varying severity.

METHODS: A total of 205 patients with prediagnosed preeclampsia were included in this prospective cohort study. Patients were allocated into one of the three groups categorized by severity of disease, as follows: gestational hypertension, group 1 (n = 41); preeclampsia, group 2 (n = 88); and severe preeclampsia, group 3 (n = 76). We assessed the spot urine PCRs to determine significant proteinuria and the magnitude of proteinuria in these groups.

RESULTS: The spot urine PCR was 0.53, with 81% sensitivity and 93% specificity to detect significant proteinuria. A significant correlation was found between PCR and 24-hour total proteinuria in group 1 (r = 0.473, P = 0.002). There were also significant correlations in group 2 (r = 0.814, P < 0.001) and group 3 (r = 0.912, P < 0.001). The established formula using spot urine PCR to estimate 24-hour total proteinuria in severe preeclampsia was Y = 832.02X + 378.74 mg (r2  = 0.8304).

CONCLUSION: Although 24-hour urine collection remains a merely reliable test to determine the degree of total proteinuria, our findings suggest that it is likely to assess the magnitude of proteinuria by the spot urine PCR, especially in severe preeclampsia.

CLINICAL TRIAL REGISTRATION: www.clinicaltrials.govNCT01623791.