Algorithms/models in the first trimester Study ref Design LoE N Aim/methods Results Comments SLR IV 38 studies Aim: To systematically review and The median number of study Methodological () critically assess the building and participants was 697 [interquartile deficiencies were frequent reporting of methods used to develop range (IQR) 377- 5126]. The median in the studies reporting risk first trimester risk prediction models for number of cases of pre-eclampsia prediction models for pre-eclampsia. per model was 37 (IQR 19-97). The This may limit median number of risk predictors was their reliability and validity. Methods: Search of PubMed and 5 (IQR 3.75-7). In 22% of the models, EMBASE databases from inception to Studies included that are the number of events per variable July 2013. Selection criteria Logistic also included in this review was fewer than the commonly regression model for predicting the risk were: and (), (), () () recommended value of 10 events per of pre-eclampsia in the first trimester, predictor; this proportion increased to including uterine artery Doppler among 94% in models for early independent variables. We extracted Treatment and handling information on study design, outcome of missing data were not reported in definition, participant recruitment, 37 models. Only three models sample size and number of events, risk reported model validation. predictors and their selection and treatment, model-building strategies, missing data, overfitting and validation.
Algorithms/models in the first trimester Study ref Design LoE N Aim/methods Results Comments () SLR IV 38 studies Aim: To systematically review and critically assess the building and reporting of methods used to develop first trimester risk prediction models for pre-eclampsia. Methods: Search of PubMed and EMBASE databases from inception to July 2013. Selection criteria 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, missing data, overfitting and validation. The median number of study participants was 697 [interquartile range (IQR) 377- 5126]. The median number of cases of pre-eclampsia per model was 37 (IQR 19-97). The median number of risk predictors was 5 (IQR 3.75-7). In 22% of the models, the number of events per variable was fewer than the commonly recommended value of 10 events per predictor; this proportion increased to 94% in models for early Treatment and handling of missing data were not reported in 37 models. Only three models reported model validation. Methodological deficiencies were frequent in the studies reporting risk prediction models for This may limit their reliability and validity. Studies included that are also included in this review were: (), (), () and ()