The effect of ethnicity on the performance of protein‐creatinine ratio in the prediction of significant proteinuria in pregnancies at risk of or with established hypertension: an implementation audit and cost implications

The replacement of 24‐h urine collection by protein‐creatinine ratio ( PCR ) for the diagnosis of preeclampsia has been recently recommended. However, the literature is conflicting and there are concerns about the impact of demographic characteristics on the performance of PCR . Material and methods This was an implementation audit of the introduction of PCR in a London Tertiary obstetric unit. The performance of PCR in the prediction of proteinuria ≥300 mg/day was assessed in 476 women with suspected preeclampsia who completed a 24‐h urine collection and an untimed urine sample for PCR calculation. Multivariate logistic regression was used to assess the independent predictors of significant proteinuria. Results In a pregnant population, ethnicity and PCR are the main predictors of ≥300 mg proteinuria in a 24‐h urine collection. A PCR cut‐off of 30 mg/mmol would have incorrectly classified as non‐proteinuric, 41.4% and 22.9% of black and non‐black women, respectively. Sensitivity of 100% is achieved at cut‐offs of 8.67 and 20.56 mg/mmol for black and non‐black women, respectively. Applying these levels as a screening tool to inform the need to perform a 24‐h urine collection in 1000 women, would lead to a financial saving of €2911 in non‐black women and to an additional cost of €3269 in black women. Conclusions Our data suggest that a move from screening for proteinuria with a 24‐h urine collection to screening with urine PCR is not appropriate for black populations. However, the move may lead to cost‐saving if used in the white population with a PCR cut‐off of 20.5.