Properties of statistical methods for indirect and mixed treatment comparison - a computer simulation evaluation

人们（例如：NICE、NHS管理者、医生和病人）可能不得不从几种不同的疾病治疗方法中选择最具成本效益的治疗方法。治疗选择最可信的证据来自随机对照试验中不同治疗的直接比较。然而，许多治疗方法尚未在试验中进行直接比较。即使没有直接比较试验的证据，人们仍然需要决定哪种治疗是最好的。统计方法已经发展到可以通过使用不同试验的数据间接比较不同的治疗方法。有几种简单或复杂的方法可以间接比较一种疾病的不同治疗方法。所有这些方法都是基于一定的假设，使用这些统计方法的结果有时可能是不正确的。间接比较的误导或错误结果可能导致选择错误的治疗方法，造成严重的健康和费用后果。本研究是一项计算机实验研究，旨在对间接比较的统计方法进行综合评价。使用真实临床试验的数据来评估统计方法的一个困难是，我们通常不这样做。我知道什么，真的吗？价值是要估计的。这一困难在计算机模拟研究中很容易克服。计算机模拟研究就像实验室研究，研究人员可以控制实验条件。我们将使用计算机在各种假设情况下生成模拟临床试验（也就是说，我们假设我们知道什么是真实的？）治疗效果为)。可用的间接比较统计方法将用于分析模拟试验。用不同统计方法估计的治疗效果将与已知的？治疗效果。然后我们将能够检查不同方法在不同情况下的有用性和局限性。模拟研究的结果将有助于为适当使用间接比较方法提供建议，并防止在选择治疗方法时做出错误的决定。

People (for example: NICE, NHS managers, doctors and patients) may have to select the most cost-effective treatment from several different treatments for an illness. The most believable evidence for the treatment selection is from the direct comparison of different treatments within randomised controlled trials. However, many treatments have not been directly compared in trials. Even without evidence from direct comparison trials, people still have to decide which the best treatment is. Statistical methods have been developed to allow different treatments to be compared indirectly by using data from separate trials. There are several simple or complex methods to make indirect comparisons of different treatment for an illness. All these methods are based on certain assumptions, and sometimes results by using these statistical methods may be incorrect. Misleading or wrong results of indirect comparisons may lead to the wrong selection of treatments with important health and cost consequences. The proposed research is a computer experimental study to comprehensively evaluate the statistical methods for indirect comparison. One difficulty in evaluating statistical methods using data from real clinical trials is that we usually don?t know what ?true? value is to be estimated. This difficulty can be easily overcome in a computer simulation study. A computer simulation study is like a laboratory study in which experimental conditions can be controlled by investigators. We will use the computer to generate simulated clinical trials under various assumed situations (that is, we assume we know what the ?true? treatment effect is). Available statistical methods for indirect comparison will be used to analyse simulated trials. The estimated treatment effects by different statistical methods will be compared with known ?true? treatment effects. Then we will be able to check the usefulness and limitations of different methods under various circumstances. Findings from the propose simulation study will help provide recommendations on appropriate use of indirect comparison methods, and prevent wrong decisions in the selection of treatments.