用干预机制评估的临床试验:注意功率和样本大小计算
Kim May Lee1, Jennifer Hellier2, Richard Emsley2
1Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, London, SE5 8AF, UK. kim.lee@kcl.ac.uk.
Trials
|August 6, 2024
概括
调解分析的样本大小计算必须考虑调解者-结果路径强度. 如果不这样做,可能会导致研究不足以检测总效果,这对于治疗意图分析至关重要.
科学领域:
- 生物统计学 生物统计学
- 统计力量分析 统计力量分析
- 因果推理因果推理
背景情况:
- 调解分析检查通过调解器的间接影响,通常是对初级治疗效果估计的次要影响.
- 现有的调解力研究主要侧重于检测间接效应,忽视了总效应力.
- 调解途径强度对检测总效应的影响仍未得到充分探索.
研究的目的:
- 评估调解途径强度与测试总治疗效果的统计能力之间的关系.
- 评估传统计算的样本大小如何受到调解途径大小的影响.
- 研究不同调解路径强度对检测治疗意图效应能力的影响.
主要方法:
- 使用常规调解模型与连续调解器和正常结果进行了模拟研究.
- 数据是在不同场景中生成的,不同场景的调解路径大小不同,同时保持总效果不变.
- 使用线性回归估计了总效应,并评估了双面测试的功率.
主要成果:
- 估计的总效应保持不偏,但其标准误差随着介质-结果路径大小和介质残余误差可变性而增加.
- 测试总效应的统计能力始终低于计划,当调解器-结果路径是实质性的,样本大小是天真地计算时.
- 分析结果证实了调解器-结果路径,而不是干预-调解器路径,影响了总效应测试功率.
结论:
- 对于疗效和机制研究的样本大小计算需要考虑调解者-结果关联.
- 如果未能将样本大小调整为调解器-结果路径,则可能无法检测总效应或治疗意图效应.
- 对影响大小考虑的调整可以纳入调解器-结果路径大小及其剩余误差.
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