Controlled clinical trials
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Control Clin Trials · Oct 1997
Meta AnalysisThe relationship between study design, results, and reporting of randomized clinical trials of HIV infection.
We examined whether the study design of randomized clinical trials for medications against human immunodeficiency virus (HIV) may affect the results and whether the outcomes of these trials affect reporting and publication. We used a database of 71 published randomized HIV-related drug efficacy trials and considered the following study design factors: endpoint definition and method of analysis, masked design, sample size, and duration of follow-up. Large variation was noted in the methods of analysis for surrogate endpoints. ⋯ We identified several examples of trials with "negative" results that have remained unpublished for a long time. In conclusion, study design factors may have an impact on the magnitude and significance of the treatment effect in HIV-related trials. Bias in reporting can further affect the information that these studies provide.
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Control Clin Trials · Feb 1996
Meta AnalysisAssessing the quality of reports of randomized clinical trials: is blinding necessary?
It has been suggested that the quality of clinical trials should be assessed by blinded raters to limit the risk of introducing bias into meta-analyses and systematic reviews, and into the peer-review process. There is very little evidence in the literature to substantiate this. This study describes the development of an instrument to assess the quality of reports of randomized clinical trials (RCTs) in pain research and its use to determine the effect of rater blinding on the assessments of quality. ⋯ These items were scored consistently by all the raters regardless of background and could discriminate between reports from the different samples. Blind assessments produced significantly lower and more consistent scores than open assessments. The implications of this finding for systematic reviews, meta-analytic research and the peer-review process are discussed.