Burke H B
University of Nevada School of Medicine, Washoe Medical Center, Reno 89520.
J Cell Biochem Suppl. 1994;19:278-82.
A variable that predicts an outcome with sufficient accuracy is called a predictive factor. Predictive factors can be divided into three types based on the outcomes to be predicted and on the accuracy with which they can be predicted. These three types include risk factors, where the main outcome of interest is incidence and the predictive accuracy is less than 100%; diagnostic factors, where the main outcome of interest is also incidence but the predictive accuracy is almost 100%; and prognostic factors, where the main outcome of interest is death and the predictive accuracy is variable. Surrogate outcomes are predictive factors that are used for a purpose beyond the prediction of an outcome--surrogate outcomes are predictive factors that are substituted for the true outcome in order to determine the effectiveness of an intervention. Surrogate outcomes used in clinical trials are called intermediate endpoints and surrogate endpoints. Predictive factors used as surrogate outcomes have a poor accuracy rate in predicting the true outcome; aggregating risk factors increases predictive accuracy. Artificial neural networks effectively combine predictive factors. Aggregating predictive factors increases the degree of linkage of the surrogate outcome to the true outcome. The resulting increase in predictive accuracy allows enrollment of people most likely to benefit from intervention. This increases the trial's efficiency, reducing the number of people required to assess a chemopreventive agent.
能够以足够的准确性预测结果的变量称为预测因素。根据要预测的结果以及预测的准确性，预测因素可分为三种类型。这三种类型包括风险因素，其关注的主要结果是发病率且预测准确性低于100%；诊断因素，其关注的主要结果也是发病率但预测准确性几乎为100%；以及预后因素，其关注的主要结果是死亡且预测准确性各不相同。替代结局是用于预测结果之外目的的预测因素——替代结局是为确定干预措施的有效性而替代真实结局的预测因素。临床试验中使用的替代结局称为中间终点和替代终点。用作替代结局的预测因素在预测真实结局方面准确率较低；汇总风险因素可提高预测准确性。人工神经网络有效地组合预测因素。汇总预测因素可增加替代结局与真实结局的关联程度。由此提高的预测准确性使得能够招募最有可能从干预中受益的人群。这提高了试验效率，减少了评估化学预防剂所需的人数。
