Blinded trials taken to the test:: an analysis of randomized clinical trials that report tests for the success of blinding
Blinded trials taken to the test:: an analysis of randomized clinical trials that report tests for the success of blinding
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DOI：
10.1093/ije/dym020
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发表时间：
2007-06-01
影响因子：
7.7
通讯作者：
Brorson, S.
中科院分区：
文献类型：
--
作者：
Hrobjartsson, A.;Forfang, E.;Brorson, S.
背景：在随机临床试验中，盲法可以减少偏倚，但盲法可能不成功。我们的目的是评估随机临床试验测试盲法成功的频率、所涉及的方法以及盲法被报告为成功的频率。方法我们分析了2001年发表的Cochrane中央对照试验登记处收录的盲法随机临床试验的随机样本。我们确定了1599个盲法试验，并注意他们是否进行了任何盲法成功的测试。我们还随机选择了200个没有报告任何此类测试的试验，并向通讯作者发送了一份调查问卷，询问他们是否进行了任何测试。结果1599个试验中有31个（2%）报告了盲法试验的成功。测试方法各不相同，报告通常是不完整的。31个试验中有14个（45%）认为盲法是成功的，10个（32%）认为不清楚。在报告盲法不成功的7项试验（23%）中，6项试验结果偏倚的风险要么没有得到解决，要么被忽略。我们收到了来自试验作者的130份问卷（65%），其中15份（12%）告知他们进行过但未发表过试验。结论盲法很少被检测。测试方法各不相同，测试和测试结果的报告是不完整的。如何最好地评估盲法在方法学上存在相当大的不确定性，迫切需要改进方法学和改进报告。
Background Blinding can reduce bias in randomized clinical trials, but blinding procedures may be unsuccessful. Our aim was to assess how often randomized clinical trials test the success of blinding, the methods involved and how often blinding is reported as being successful.Methods We analysed a random sample of blinded randomized clinical trials indexed in the The Cochrane Central Register of Controlled Trials and published in 2001. We identified 1599 blinded trials, and noted if they had conducted any test for the success of blinding. We also selected 200 trials randomly that did not report any such test, and sent a questionnaire to the corresponding authors asking them if they had conducted any tests.Results Thirty-one out of 1599 trials (2%) reported tests for the success of blinding. Test methods varied, and reporting was generally incomplete. Blinding was considered successful in 14 out of the 31 trials (45%) and unclear in 10 (32%). of the seven trials (23%) reporting unsuccessful blinding the risk of a biased trial result was either not addressed or was discounted in six cases. We received 130 questionnaires from trial authors (65%) of which 15 (12%) informed that they had conducted, but not published, tests.Conclusions Blinding is rarely tested. Test methods vary, and the reporting of tests, and test results, is incomplete. There is a considerable methodological uncertainty how best to assess blinding, and an urgent need for improved methodology and improved reporting.