Department of Obstetrics and Gynecology, Duke University Health System, Durham, NC.
Department of Obstetrics and Gynecology, Duke University Health System, Durham, NC.
Am J Obstet Gynecol. 2019 May;220(5):492.e1-492.e7. doi: 10.1016/j.ajog.2019.01.232. Epub 2019 Feb 1.
The use of trial of labor after cesarean delivery calculators in the prediction of successful vaginal birth after cesarean delivery gives physicians an evidence-based tool to assist with patient counseling and risk stratification. Before deployment of prediction models for routine care at an institutional level, it is recommended to test their performance initially in the institution's target population. This allows the institution to understand not only the overall accuracy of the model for the intended population but also to comprehend where the accuracy of the model is most limited when predicting across the range of predictions (calibration).
The purpose of this study was to compare 3 models that predict successful vaginal birth after cesarean delivery with the use of a single tertiary referral cohort before continuous model deployment in the electronic medical record.
All cesarean births for failed trial of labor after cesarean delivery and successful vaginal birth after cesarean delivery at an academic health system between May 2013 and March 2016 were reviewed. Women with a history of 1 previous cesarean birth who underwent a trial of labor with a term (≥37 weeks gestation), cephalic, and singleton gestation were included. Women with antepartum intrauterine fetal death or fetal anomalies were excluded. The probability of successful vaginal birth after cesarean delivery was calculated with the use of 3 prediction models: Grobman 2007, Grobman 2009, and Metz 2013 and compared with actual vaginal birth after cesarean delivery success. Each model's performance was measured with the use of concordance indices, Brier scores, and calibration plots. Decision curve analysis identified the range of threshold probabilities for which the best prediction model would be of clinical value.
Four hundred four women met the eligibility criteria. The observed rate of successful vaginal birth after cesarean delivery was 75% (305/404). Concordance indices were 0.717 (95% confidence interval, 0.659-0.778), 0.703 (95% confidence interval, 0.647-0.758), and 0.727 (95% confidence interval, 0.669-0.779), respectively. Brier scores were 0.172, 0.205, and 0.179, respectively. Calibration demonstrated that Grobman 2007 and Metz vaginal birth after cesarean delivery models were most accurate when predicted probabilities were >60% and were beneficial for counseling women who did not desire to have vaginal birth after cesarean delivery but had a predicted success rates of 60-90%. The models underpredicted actual probabilities when predicting success at <60%. The Grobman 2007 and Metz vaginal birth after cesarean delivery models provided greatest net benefit between threshold probabilities of 60-90% but did not provide a net benefit with lower predicted probabilities of success compared with a strategy of recommending vaginal birth after cesarean delivery for all women .
When 3 commonly used vaginal birth after cesarean delivery prediction models are compared in the same population, there are differences in performance that may affect an institution's choice of which model to use.
在剖宫产术后试产计算器的预测中，使用成功的阴道分娩后剖宫产率为医生提供了一种基于证据的工具，以协助患者咨询和风险分层。在将预测模型部署到机构的常规护理之前，建议先在机构的目标人群中测试其性能。这使机构不仅能够了解模型对预期人群的总体准确性，而且还能够理解模型在预测范围内（校准）的准确性最有限的地方。
本研究的目的是在电子病历中连续部署模型之前，使用单一的三级转诊队列来比较 3 种预测剖宫产术后成功阴道分娩的模型。
对 2013 年 5 月至 2016 年 3 月期间在学术医疗系统中发生剖宫产失败试产后和成功阴道分娩后的所有剖宫产进行了回顾性分析。纳入了既往有 1 次剖宫产史，且进行了试产的足月（≥37 周妊娠）、头位和单胎妊娠的女性。排除了产前宫内胎儿死亡或胎儿畸形的女性。使用 3 种预测模型（Grobman 2007、Grobman 2009 和 Metz 2013）计算剖宫产术后成功阴道分娩的概率，并将其与实际阴道分娩后的成功率进行比较。使用一致性指数、Brier 评分和校准图来衡量每个模型的性能。决策曲线分析确定了最佳预测模型具有临床价值的阈值概率范围。
符合纳入标准的 404 名女性。实际剖宫产术后成功阴道分娩率为 75%（305/404）。一致性指数分别为 0.717（95%置信区间，0.659-0.778）、0.703（95%置信区间，0.647-0.758）和 0.727（95%置信区间，0.669-0.779）。Brier 评分分别为 0.172、0.205 和 0.179。校准表明，当预测概率>60%时，Grobman 2007 和 Metz 阴道分娩后剖宫产模型最为准确，有利于对那些不希望进行阴道分娩后剖宫产但预测成功率为 60-90%的女性进行咨询。当预测概率<60%时，模型会低估实际概率。Grobman 2007 和 Metz 阴道分娩后剖宫产模型在 60-90%的阈值概率之间提供了最大的净效益，但与推荐所有女性进行阴道分娩后剖宫产的策略相比，在较低的预测成功率阈值下并没有提供净效益。
当在同一人群中比较 3 种常用的阴道分娩后剖宫产预测模型时，其性能存在差异，这可能会影响机构选择使用哪种模型。
