Bell D S
Department of Medicine, UCLA School of Medicine, USA.
Proc AMIA Annu Fall Symp. 1997:173-7.
Many patients who need coronary angiography fail to get it and they have decreased survival as a result. This study demonstrates the use of decision analysis to predict the survival value of an alerting system for necessary angiography.
Data on the use of angiography and survival after myocardial infarction (MI) were taken from a published cohort study. The expected value of information (EVI) was calculated for alerts that angiography is necessary. Maximal EVI was estimated by assuming that alert advice is always followed. Sensitivity analysis relaxed that assumption. Hypothetical data were generated to demonstrate EVI analysis for narrower subcohorts.
A maximally effective alerting system would increase survival in this cohort by 2.2% over 1-4 years after MI. The system would therefore need to be applied to 46 people to prevent one death. Its effectiveness would decrease linearly with decreasing adherence to its advice. Given sufficiently detailed outcome and prevalence data, EVI analysis could also predict the survival value of the system's individual data elements.
An alerting system that ensures necessary angiography post-MI should have a survival value comparable to the value of t-PA over streptokinase. EVI analysis provides a framework for predicting the overall effectiveness of information systems and for understanding the contribution of individual features to a system's effectiveness.
许多需要进行冠状动脉造影的患者未能接受该检查，结果导致生存率下降。本研究展示了如何运用决策分析来预测用于提示必要造影检查的警报系统的生存价值。
关于心肌梗死（MI）后造影检查的使用情况及生存数据取自一项已发表的队列研究。计算了提示造影检查必要时的信息期望值（EVI）。通过假设始终遵循警报建议来估计最大EVI。敏感性分析放宽了该假设。生成假设数据以展示针对更窄亚组的EVI分析。
一个最大程度有效的警报系统在心肌梗死后1至4年可使该队列的生存率提高2.2%。因此，该系统需要应用于46人才能预防一例死亡。其有效性会随着对其建议的依从性降低而呈线性下降。给定足够详细的结局和患病率数据，EVI分析还可预测该系统单个数据元素的生存价值。
确保心肌梗死后进行必要造影检查的警报系统应具有与t-PA优于链激酶相当的生存价值。EVI分析提供了一个框架，用于预测信息系统的整体有效性以及理解各个特征对系统有效性的贡献。
