Drummond M, Coyle D
University of York.
Int J Technol Assess Health Care. 1998 Summer;14(3):405-18. doi: 10.1017/s0266462300011399.
An increasing number of economic evaluations are being conducted alongside clinical trials. While this practice offers the prospect of collecting comprehensive and accurate cost data, it requires considerable time and effort. In the case of clinical data, key analytic decisions such as which data to collect and sample size are often made with reference to smaller (pilot) trials. However, this approach is not normally followed in the case of economic evaluation. This study was based on a recently completed health technology assessment comparing conventional radiotherapy with continuous hyperfractionated accelerated radiotherapy (CHART) for patients with head and neck cancer or carcinoma of the bronchus. In the full health technology assessment, cost data were available for 526 head and neck patients (314 CHART and 212 conventional therapy) and 286 bronchus patients (175 CHART and 109 conventional therapy). In order to simulate a pilot study, data were extracted for the patients recruited to both trials in the first 3 months. These were then compared with the full data set in order to assess whether such a pilot study would have given useful guidance on: a) the usefulness of undertaking a full study; b) the sample size required; and c) the important resource items for which comprehensive data collection would be required. Pilot studies can be helpful in determining the likely advantages of undertaking full economic evaluations and in identifying important resource items. Therefore, it is important that clinical researchers and research funding bodies create the necessary time window to enable such studies to take place. However, formal sample size calculations are more difficult to perform on limited data, since they also require knowledge of the unit cost (or prices) to be attached to the resource items and the correlation between costs and clinical effects.
越来越多的经济评估与临床试验同时进行。虽然这种做法有望收集全面且准确的成本数据，但它需要大量的时间和精力。就临床数据而言，诸如收集哪些数据以及样本量等关键分析决策通常是参照规模较小的（试点）试验做出的。然而，在经济评估中通常并不采用这种方法。本研究基于一项最近完成的卫生技术评估，该评估比较了常规放疗与持续超分割加速放疗（CHART）对头颈部癌或支气管癌患者的疗效。在完整的卫生技术评估中，有526名头颈部患者（314名接受CHART治疗，212名接受常规治疗）和286名支气管患者（175名接受CHART治疗，109名接受常规治疗）的成本数据。为了模拟一项试点研究，提取了在前3个月纳入两项试验的患者的数据。然后将这些数据与完整数据集进行比较，以评估这样一项试点研究是否会在以下方面提供有用的指导：a）进行全面研究的有用性；b）所需的样本量；c）需要收集全面数据的重要资源项目。试点研究有助于确定进行全面经济评估可能带来的优势，并有助于确定重要的资源项目。因此，临床研究人员和研究资助机构创造必要的时间窗口以使此类研究能够开展非常重要。然而，在有限的数据上进行正式的样本量计算更加困难，因为这还需要了解与资源项目相关的单位成本（或价格）以及成本与临床效果之间的相关性。
