BACKGROUND Guidelines recommend identifying in early pregnancy women at elevated risk of pre-eclampsia. The aim of this study was to develop and validate a pre-eclampsia risk prediction model for nulliparous women attending routine antenatal care "the Western Sydney (WS) model"; and to compare its performance with the National Institute of Health and Care Excellence (NICE) risk factor-list approach for classifying women as high-risk. METHODS This retrospective cohort study included all nulliparous women who gave birth in three public hospitals in the Western-Sydney-Local-Health-District, Australia 2011-2014. Using births from 2011 to 2012, multivariable logistic regression incorporated established maternal risk factors to develop and internally validate the WS model. The WS model was then externally validated using births from 2013 to 2014, assessing its discrimination and calibration. We fitted the final WS model for all births from 2011 to 2014, and compared its accuracy in predicting pre-eclampsia with the NICE approach. RESULTS Among 12,395 births to nulliparous women in 2011-2014, there were 293 (2.4%) pre-eclampsia events. The WS model included: maternal age, body mass index, ethnicity, multiple pregnancy, family history of pre-eclampsia, autoimmune disease, chronic hypertension and chronic renal disease. In the validation sample (6201 births), the model c-statistic was 0.70 (95% confidence interval 0.65-0.75). The observed:expected ratio for pre-eclampsia was 0.91, with a Hosmer-Lemeshow goodness-of-fit test p-value of 0.20. In the entire study sample of 12,395 births, 374 (3.0%) women had a WS model-estimated pre-eclampsia risk ≥8%, the pre-specified risk-threshold for considering aspirin prophylaxis. Of these, 54 (14.4%) developed pre-eclampsia (sensitivity 18% (14-23), specificity 97% (97-98)). Using the NICE approach, 1173 (9.5%) women were classified as high-risk, of which 107 (9.1%) developed pre-eclampsia (sensitivity 37% (31-42), specificity 91% (91-92)). The final model showed similar accuracy to the NICE approach when using lower risk-threshold of ≥4% to classify women as high-risk for pre-eclampsia. CONCLUSION The WS risk model that combines readily-available maternal characteristics achieved modest performance for prediction of pre-eclampsia in nulliparous women. The model did not outperform the NICE approach, but has the advantage of providing individualised absolute risk estimates, to assist with counselling, inform decisions for further testing, and consideration of aspirin prophylaxis.

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使用常规收集的孕产妇特征预测未产妇先兆子痫：模型开发和验证研究。

背景技术指南建议在妊娠早期确定先兆子痫风险较高的妇女。本研究的目的是为参加常规产前护理的未产妇开发和验证先兆子痫风险预测模型“西悉尼（WS）模型”。并将其与美国国立卫生研究院的风险因素列表方法进行比较，以将妇女归类为高风险。方法这项回顾性队列研究包括2011-2014年澳大利亚西悉尼本地健康区的三所公立医院分娩的所有未产妇。利用2011年至2012年的出生人数，多变量logistic回归纳入了已建立的孕产妇危险因素，以开发和内部验证WS模型。然后使用2013年至2014年的出生人数对WS模型进行外部验证，评估其辨别力和校准值。我们为2011年至2014年的所有婴儿拟合了最终的WS模型，并使用NICE方法比较了其预测先兆子痫的准确性。结果在2011年至2014年，共有12395例未生育妇女分娩，其中293例（2.4％）先兆子痫事件。WS模型包括：孕妇年龄，体重指数，种族，多胎妊娠，先兆子痫的家族史，自身免疫性疾病，慢性高血压和慢性肾脏病。在验证样本（6201例出生）中，模型c统计量为0.70（95％置信区间0.65-0.75）。子痫前期的观察到的预期比率为0.91，Hosmer-Lemeshow拟合优度检验的p值为0.20。在整个12395名婴儿的研究样本中，有374名（3。（0％）妇女的WS模型估计先兆子痫风险≥8％，这是考虑预防阿司匹林的既定风险阈值。其中54（14.4％）个先兆子痫（敏感性18％（14-23），特异性97％（97-98））。使用NICE方法，将1173名（9.5％）妇女定为高危人群，其中107名（9.1％）患有先兆子痫（敏感性37％（31-42），特异性91％（91-92））。当使用≥4％的较低风险阈值将妇女分类为先兆子痫的高风险时，最终模型显示出与NICE方法相似的准确性。结论结合了容易获得的孕产妇特征的WS风险模型在未产妇预测先兆子痫中表现不佳。该模型并没有优于NICE方法，但具有提供个性化绝对风险估算值的优势，