Prediction of pre‐eclampsia‐related complications in women with suspected or confirmed pre‐eclampsia: development and internal validation of clinical prediction model

OBJECTIVE: A model that can predict reliably the risk of pre‐eclampsia (PE)‐related pregnancy complications does not exist. The aim of this study was to develop and validate internally a clinical prediction model to predict the risk of a composite outcome of PE‐related maternal and fetal complications within 7, 14 and 30 days of testing in women with suspected or confirmed PE. METHODS: The data for this study were derived from a prospective, multicenter, observational cohort study on women with a singleton pregnancy and suspected or confirmed PE at 20 to < 37 weeks' gestation. For the development of the prediction model, the possible contribution of clinical and standard laboratory variables, as well as the biomarkers soluble fms‐like tyrosine kinase‐1 (sFlt‐1), placental growth factor (PlGF) and their ratio, in the prediction of a composite outcome of PE‐related complications, consisting of maternal and fetal adverse events within 7, 14 and 30 days, was explored using multivariable competing‐risks regression analysis. The discriminative ability of the model was assessed using the concordance (c‐) statistic. A bootstrap validation procedure with 500 replications was used to correct the estimate of the prediction model performance for optimism and to compute a shrinkage factor for the regression coefficients to correct for overfitting. RESULTS: Among 384 women with suspected or confirmed PE, 96 (25%) had an adverse PE‐related outcome at any time after hospital admission. Important predictors of adverse PE‐related outcome included sFlt‐1/PlGF ratio, gestational age at the time of biomarker measurement and protein‐to‐creatinine ratio as continuous variables. The c‐statistics (corrected for optimism) for developing a PE‐related complication within 7, 14 and 30 days were 0.89, 0.88 and 0.87, respectively. There was limited overfitting, as indicated by a shrinkage factor of 0.91. CONCLUSIONS: We propose a simple clinical prediction model with good discriminative performance to predict PE‐related complications. Determination of its usefulness in clinical practice awaits further investigation and external validation. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.