Centre-specific or average unit costs in multi-centre studies? Some theory and simulation
通过模拟临床试验，比较了两种成本收集方法：一种使用跨中心平均单位成本，另一种使用中心特定单位成本和资源量，发现两种方法得出的平均治疗成本存在统计差异，建议在多中心研究中谨慎处理成本数据。
Costing issues are increasingly being addressed in multi-centre studies. In this paper, two methods for collecting costing information are compared within a simulated clinical trial setting. One method estimates average treatment costs by applying unit costs averaged across treatment centres to centre-specific volumes of resource use. The second uses centre-specific information for both the unit costs and the resource volumes, and then averages across centres. Using a pre-specified production relation between the different volumes of resource use, and simulating changes in unit costs, it is shown that these two methods result in statistically different estimates of average treatment costs. This finding holds, regardless of the degree of substitutability between the resource volumes, except when considerable uncertainty surrounds treatment centre responses to relative changes in unit costs. The findings suggest that a more cautious approach should be adopted in the collection, calculation and interpretation of treatment costs in multi-centre studies.