STATIN trial: predictive performance of competing-risk model in screening for pre-eclampsia at 35-37 weeks' gestation.

Objective To examine the predictive performance of the previously reported competing risks model of screening for preeclampsia (PE) at 35-37 weeks' gestation by combinations of maternal risk factors, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), serum placental growth factor (PlGF) and serum soluble fms-like tyrosine kinase-1 (sFLT-1) in the validation dataset derived from the screened population of the STATIN study. Methods This was a prospective third-trimester multicenter study of screening for PE in 29,677 singleton pregnancies by means of a previously reported algorithm that combines maternal risk factors and biomarkers. Women in the high-risk group were invited to participate in a trial of pravastatin versus placebo but the trial showed no evidence of an effect of pravastatin in the prevention of PE. Patient-specific risks of delivery with PE were calculated using the competing risks model and the performance of screening for PE by maternal risk factors alone and various combinations of risk factors and MAP, UtA-PI, PLGF and sFLT-1 was assessed. We examined the predictive performance of the model by first, the ability of the model to discriminate between the PE and no PE groups using the area under the receiver operating characteristic (AUROC) curve and the detection rate (DR) at fixed false positive rate (FPR) of 10%, and second, calibration by measurements of calibration slope and calibration-in-the-large. Results The study population of 29,677 pregnancies contained 653 that developed PE. In screening for PE by a combination of maternal risk factors, MAP, PlGF and sFLT-1 (triple test), the DR at 10% FPR was 79% (95% CI 76, 82%) and the results were consistent with the data used for developing the algorithm. Addition of UtA-PI did not improve the prediction provided by the triple test. The AUROC curve was 0.923 (95% CI 0.913, 0.932) demonstrating a very high discrimination between affected and unaffected pregnancies. Similarly, the calibration slope was 0.875 (95% CI 0.831, 0.919) demonstrating a good agreement between the predicted risks and observed incidence of PE. Conclusion The competing risks model provides an effective and reproducible method for third-trimester prediction of term PE. This article is protected by copyright. All rights reserved.