Department of Epidemiology & Preventive Medicine, Monash University, 89 Commercial Road, Melbourne, VIC 3004, Australia.
Eur J Cardiothorac Surg. 2010 May;37(5):1086-92. doi: 10.1016/j.ejcts.2009.11.021. Epub 2010 Feb 8.
Population-specific risk models are required to build consumer and provider confidence in clinical service delivery, particularly when the risks may be life-threatening. Cardiac surgery carries such risks. Currently, there is no model developed on the Australian cardiac surgery population and this article presents a novel risk prediction model for the Australian cohort with the aim to provide a guide for the surgeons and patients in assessing preoperative risk factors for cardiac surgery.
This study aims to identify preoperative risk factors associated with 30-day mortality following cardiac surgery for an Australian population and to develop a preoperative model for risk prediction.
All patients (23016) undergoing cardiac surgery between July 2001 and June 2008 recorded in the Australian Society of Cardiac and Thoracic Surgeons (ASCTS) database were included in this analysis. The data were divided randomly into model creation (13810, 60%) and model validation (9206, 40%) sets. The model was developed on the creation set and then validated on the validation set. The bootstrap sampling and automated variable selection methods were used to develop several candidate models. The final model was selected from this group of candidate models by using prediction mean square error (MSE) and Bayesian Information Criteria (BIC). Using a multifold validation, the average receiver operating characteristic (ROC), p-value for Hosmer-Lemeshow chi-squared test and MSE were obtained. Risk thresholds for low-, moderate- and high-risk patients were defined. The expected and observed mortality for various risk groups were compared. The multicollinearity and first-order interaction effect between clinically meaningful risk factors were investigated.
A total of 23016 patients underwent cardiac surgery and the 30-day mortality rate was 3.2% (728 patients). Independent predictors of mortality in the model were: age, sex, the New York Heart Association (NYHA) class, urgency of procedure, ejection fraction estimate, lipid-lowering treatment, preoperative dialysis, previous cardiac surgery, procedure type, inotropic medication, peripheral vascular disease and body mass index (BMI). The model had an average ROC 0.8223 (95% confidence interval (CI): 0.8118-0.8227), p-value 0.8883 (95% CI: 0.8765-0.90) and MSE 0.0251 (95% CI: 0.02515-0.02516). The validation set had observed mortality 3.0% (95% CI: 2.7-3.3%) and predicted mortality 2.9% (95% CI: 2.6-3.2%). The low-risk group (additive score 0-3) had 0.6% observed mortality (95% CI: 0.3-0.9%) and 0.5% predicted mortality (95% CI: 0.2-0.8%). The moderate-risk group (additive score 4-9) had 1.7% observed mortality (95% CI: 1.2-2.2%) and 1.4% predicted mortality (95% CI: 1.0-1.8%). The observed mortality for the high-risk group (additive score 9 plus) was 6.7% (95% CI: 5.8-7.6%) and the expected mortality was 6.7% (95% CI: 5.8-7.6%).
A preoperative risk prediction model for 30-day mortality was developed for the Australian cardiac surgery population.
需要针对特定人群制定风险模型，以建立患者和医疗服务提供者对临床服务的信心，尤其是在风险可能危及生命的情况下。心脏手术就存在此类风险。目前，尚未针对澳大利亚心脏手术人群开发风险模型，本文旨在为澳大利亚队列开发一种新的风险预测模型，以便为外科医生和患者提供术前风险因素评估的指南。
本研究旨在确定与澳大利亚人群心脏手术后 30 天死亡率相关的术前风险因素，并开发术前风险预测模型。
纳入了澳大利亚心胸外科医生协会（ASCTS）数据库中 2001 年 7 月至 2008 年 6 月期间接受心脏手术的所有患者（23016 例）。将数据随机分为模型建立（13810 例，占 60%）和模型验证（9206 例，占 40%）两组。在建立组中开发模型，然后在验证组中进行验证。使用自举抽样和自动变量选择方法开发了几个候选模型。通过预测均方误差（MSE）和贝叶斯信息准则（BIC）从候选模型组中选择最终模型。使用多重验证，获得平均接收者操作特征（ROC）、Hosmer-Lemeshow 卡方检验的 p 值和 MSE。为低危、中危和高危患者定义风险阈值。比较各种风险组的预期和观察死亡率。研究了有临床意义的风险因素之间的多重共线性和一阶交互效应。
共有 23016 例患者接受了心脏手术，30 天死亡率为 3.2%（728 例）。模型中的独立死亡预测因子为：年龄、性别、纽约心脏协会（NYHA）分级、手术紧急程度、射血分数估计值、降脂治疗、术前透析、既往心脏手术、手术类型、正性肌力药物、外周血管疾病和体重指数（BMI）。该模型的平均 ROC 为 0.8223（95%置信区间[CI]：0.8118-0.8227），p 值为 0.8883（95%CI：0.8765-0.90），MSE 为 0.0251（95%CI：0.02515-0.02516）。验证组观察死亡率为 3.0%（95%CI：2.7-3.3%），预测死亡率为 2.9%（95%CI：2.6-3.2%）。低危组（附加评分 0-3）观察死亡率为 0.6%（95%CI：0.3-0.9%），预测死亡率为 0.5%（95%CI：0.2-0.8%）。中危组（附加评分 4-9）观察死亡率为 1.7%（95%CI：1.2-2.2%），预测死亡率为 1.4%（95%CI：1.0-1.8%）。高危组（附加评分 9 分及以上）观察死亡率为 6.7%（95%CI：5.8-7.6%），预测死亡率为 6.7%（95%CI：5.8-7.6%）。
为澳大利亚心脏手术人群开发了一种 30 天死亡率的术前风险预测模型。
