Bertolini G, D'Amico R, Apolone G, Cattaneo A, Ravizza A, Iapichino G, Brazzi L, Melotti R M
Laboratorio di Epidemiologia dell'Assistenza Sanitaria, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
Med Care. 1998 Sep;36(9):1371-82. doi: 10.1097/00005650-199809000-00009.
This study sought to compare the performance of the old and new versions of the Simplified Acute Physiology Score, SAPS and SAPS II, in classifying patients according to the risk of hospital mortality.
To compare the performance of the two systems, measures of association between the scores and observed mortality were adopted, together with discrimination (area under the Receiver Operating Characteristics curve) and calibration (goodness-of-fit statistics) estimates. Subjects were 1,393 eligible patients recruited during 1 month in 1994. The outcome measure was vital status at hospital discharge.
SAPS II was associated more strongly with hospital mortality than the earlier version. SAPS II also had better discrimination ability than SAPS (area under Receiver Operating Characteristics curve 0.80 versus 0.74) and predicted an overall number of deaths (416.5) closer to the observed figure (475) than SAPS (267.7). Conversely, neither SAPS nor SAPS II fitted our data. Both P values derived from goodness-of-fit statistics were lower than 0.05.
SAPS II offers a real improvement compared with SAPS in its ability to explain hospital mortality, but its standard parameters do not fit our data from Italy. The role and impact of potential determinants of this lack of fit, such as random errors and confounders related to casemix and/or quality of care should be clarified before this scoring system be used outside formal research projects. Special caution is suggested when SAPS II is adopted to predict mortality to compare intensive care unit performance across different countries and systems of care.
本研究旨在比较简化急性生理学评分（SAPS）旧版和新版（即SAPS II）在根据医院死亡风险对患者进行分类方面的表现。
为比较这两个系统的表现，采用了评分与观察到的死亡率之间的关联度量，以及鉴别力（受试者工作特征曲线下面积）和校准（拟合优度统计量）估计值。研究对象为1994年1个月内招募的1393例符合条件的患者。结局指标为出院时的生命状态。
与早期版本相比，SAPS II与医院死亡率的关联更强。SAPS II的鉴别能力也优于SAPS（受试者工作特征曲线下面积分别为0.80和0.74），且预测的死亡总数（416.5）比SAPS（267.7）更接近观察到的数字（475）。相反，SAPS和SAPS II均不适合我们的数据。拟合优度统计量得出的P值均低于0.05。
与SAPS相比，SAPS II在解释医院死亡率的能力方面有实际改进，但其标准参数不适合我们来自意大利的数据。在该评分系统用于正式研究项目之外之前，应阐明这种不匹配的潜在决定因素（如随机误差以及与病例组合和/或护理质量相关的混杂因素）的作用和影响。当采用SAPS II预测死亡率以比较不同国家和护理系统的重症监护病房表现时，建议格外谨慎。
