Feasibility of transitioning from APACHE II to SAPS III as prognostic model in a Brazilian general intensive care unit. A retrospective study

CONTEXT AND OBJECTIVE: Prognostic models reflect the population characteristics of the countries from which they originate. Predictive models should be customized to fit the general population where they will be used. The aim here was to perform external validation on two predictive models and compare their performance in a mixed population of critically ill patients in Brazil.DESIGN AND SETTING: Retrospective study in a Brazilian general intensive care unit (ICU).METHODS: This was a retrospective review of all patients admitted to a 41-bed mixed ICU from August 2011 to September 2012. Calibration (assessed using the Hosmer-Lemeshow goodness-of-fit test) and discrimination (assessed using area under the curve) of APACHE II and SAPS III were compared. The standardized mortality ratio (SMR) was calculated by dividing the number of observed deaths by the number of expected deaths.RESULTS: A total of 3,333 ICU patients were enrolled. The Hosmer-Lemeshow goodness-of-fit test showed good calibration for all models in relation to hospital mortality. For in-hospital mortality there was a worse fit for APACHE II in clinical patients. Discrimination was better for SAPS III for in-ICU and in-hospital mortality (P = 0.042). The SMRs for the whole population were 0.27 (confidence interval [CI]: 0.23 - 0.33) for APACHE II and 0.28 (CI: 0.22 - 0.36) for SAPS III.CONCLUSIONS: In this group of critically ill patients, SAPS III was a better prognostic score, with higher discrimination and calibration power.

研究背景与目的：预后模型会反映其来源国的人群特征，预测模型需针对其应用的目标人群进行定制化调整。本研究旨在针对两款预测模型开展外部验证，并在巴西的重症混合人群中对比二者的性能表现。
研究设计与研究场景：本研究为一项在巴西综合重症监护病房（intensive care unit, ICU）开展的回顾性研究。
研究方法：本研究回顾性分析了2011年8月至2012年9月期间，收治于某拥有41张床位的混合重症监护病房的全部患者。对比了急性生理学与慢性健康状况评分系统II（APACHE II）与简化急性生理学评分III（SAPS III）的校准度（采用Hosmer-Lemeshow拟合优度检验（Hosmer-Lemeshow goodness-of-fit test）评估）及区分度（采用受试者工作特征曲线下面积（area under the curve）评估）；标准化死亡率比（standardized mortality ratio, SMR）通过观察死亡数除以预期死亡数计算得出。
研究结果：本研究共纳入3333名重症监护病房患者。Hosmer-Lemeshow拟合优度检验结果显示，两款模型针对住院死亡率的校准度均表现良好；针对临床患者的住院死亡率而言，APACHE II的拟合效果欠佳。SAPS III针对ICU内死亡率及住院死亡率的区分度更优（P=0.042）。全人群的标准化死亡率比方面，APACHE II为0.27（置信区间（confidence interval, CI）：0.23~0.33），SAPS III为0.28（CI：0.22~0.36）。
研究结论：在本次研究纳入的重症患者群体中，SAPS III是更优的预后评分工具，具备更高的区分度与校准效能。