Impact of allocation concealment on conclusions drawn from meta-analyses of randomized trials
Impact of allocation concealment on conclusions drawn from meta-analyses of randomized trials
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DOI：
10.1093/ije/dym087
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发表时间：
2007-08-01
影响因子：
7.7
通讯作者：
Gotzsche, P. C.
中科院分区：
文献类型：
--
作者：
Pildal, J.;Hrobjartsson, A.;Gotzsche, P. C.
研究背景：没有充分的分配隐藏的随机试验被证明高估了实验干预的益处。我们研究了从荟萃分析得出的结论，以排除这样的trials.Material随机样本的38篇评论从科克伦图书馆2003年，第2期和其他32篇评论从PubMed在2002年访问。符合条件的评论提出了一个二元效应估计的随机对照试验的荟萃分析作为第一个统计学显着的结果，支持的结论，有利于一个interventions.Methods我们评估的方法部分的试验中，每个包括荟萃分析的充分分配隐藏。我们使用作者的方法重复了每项荟萃分析，但仅包括具有充分分配隐藏的试验。结论被定义为不支持，如果我们的结果是不具有统计学意义。结果34的70个荟萃分析包含的混合物的试验不清楚或不充分的隐藏，以及试验充分分配隐藏。4项荟萃分析仅包含充分隐藏的试验，32项仅包含不明确或不充分隐藏的试验。当仅包括具有充分隐藏的试验时，70个结论中有48个（69%; 95%置信区间：56-79%）失去了支持。支持的损失主要反映了权力的损失（患者总数减少了49%），但也转移到一个不太有益的effect.Conclusion三分之二的结论，有利于干预措施之一，不再支持，如果只有足够的分配隐藏试验。
Background Randomized trials without reported adequate allocation concealment have been shown to overestimate the benefit of experimental interventions. We investigated the robustness of conclusions drawn from meta-analyses to exclusion of such trials.Material Random sample of 38 reviews from The Cochrane Library 2003, issue 2 and 32 other reviews from PubMed accessed in 2002. Eligible reviews presented a binary effect estimate from a meta-analysis of randomized controlled trials as the first statistically significant result that supported a conclusion in favour of one of the interventions.Methods We assessed the methods sections of the trials in each included meta-analysis for adequacy of allocation concealment. We replicated each meta-analysis using the authors' methods but included only trials that had adequate allocation concealment. Conclusions were defined as not supported if our result was not statistically significant.Results Thirty-four of the 70 meta-analyses contained a mixture of trials with unclear or inadequate concealment as well as trials with adequate allocation concealment. Four meta-analyses only contained trials with adequate concealment, and 32, only trials with unclear or inadequate concealment. When only trials with adequate concealment were included, 48 of 70 conclusions (69%; 95% confidence interval: 56-79%) lost support. The loss of support mainly reflected loss of power (the total number of patients was reduced by 49%) but also a shift in the point estimate towards a less beneficial effect.Conclusion Two-thirds of conclusions in favour of one of the interventions were no longer supported if only trials with adequate allocation concealment were included.