Albumin/Creatinine Ratio for the Detection of Significant Proteinuria of Preeclampsia in Hospitalized Hypertensive Women.

Objective: Preeclampsia is a hypertensive disorder of pregnancy associated with proteinuria detected by 24-hour urine collection (≥0.3 g/24 h) or protein/creatinine ratio (≥30 mg/mmol). The albumin/creatinine ratio (ACR) is used outside pregnancy to detect abnormal amounts of albumin in the urine, but there is little data on its value in pregnancy. Our objective was to determine the diagnostic threshold for ACR to detect significant proteinuria in women investigated for preeclampsia.

Methods: A prospective observational study involving 99 hypertensive women (≥140/90 mm Hg) over 20 weeks gestation who were hospitalized at 2 Canadian tertiary centres. A 24-hour urine collection and a morning urine sample were collected. The optimal ACR threshold was determined by a receiver operating characteristic (ROC) curve using the 24-hour collection as the reference test; sensitivity and specificity analyses were performed. Maternal and perinatal characteristics were extracted from medical records.

Results: Of the 87 women who had completed urine collection, 74 (85%) had an initial diagnosis of preeclampsia and 63 (72%) had significant proteinuria confirmed by 24-hour collection. The area under the morning ROC curve was 0.92 (95% CI 0.86-0.98) and the optimal threshold obtained for the ACR was 9 mg/mmol, with a sensitivity and specificity of 84% (95% CI 73-92) and 88% (95% CI 68-97), respectively.

Conclusion: Our results suggest that an ACR threshold of 9 mg/mmol on a morning urine sample can be used to detect significant proteinuria of preeclampsia in hospitalized hypertensive women.