P14.31: First trimester risk prediction models for pre‐eclampsia based on uterine artery Doppler: a systematic review of methodology

Abstract

To systematically review and critically assess the conduct and reporting of methods used to develop first trimester risk prediction models for pre-eclampsia. Systematic search of PubMed and EMBASE databases to identify studies published before July 2013 that presented a logistic regression model for predicting the risk of pre-eclampsia in the first trimester, including uterine artery Doppler among independent variables. We extracted information on study design, outcome definition, participant recruitment, sample size and number of events, risk predictors and their selection and treatment, model building strategies and aspects of performance, missing data, overfitting and validation. The initial search identified 80 articles. A total of 26 studies was eligible for review. The median number of risk predictors was 13 (interquartile range 4.25 to 15). In 13 studies (50%), the number of events per variable was fewer than the commonly recommended value of ten events per predictor. Methods not recommended to select risk predictors for inclusion in the multivariate model were used in 7 studies (27%). Treatment and handling of missing data were not reported in 12 studies (46%). None of the studies reported model validation. We found frequent methodological deficiencies in studies reporting risk prediction models for pre-eclampsia. This limitis their reliability and applicability.