The importance of quality of primary studies in producing unbiased systematic reviews
The importance of quality of primary studies in producing unbiased systematic reviews
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DOI：
10.1001/archinte.156.6.661
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发表时间：
1996-03-25
影响因子：
--
通讯作者：
Jadad, AR
中科院分区：
文献类型：
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作者：
Khan, KS;Daya, S;Jadad, AR
背景：传统的、主要是定性的证据审查现在正在让位于更加结构化的系统概述，这些概述使用定量方法来计算治疗的总体效果。后一种方法取决于主要研究的质量，如果方法学质量较差，则可能会引入偏差。目的：检验荟萃分析中纳入质量较差的试验会使结论产生偏差并产生治疗效果错误估计的假设。方法：对患有少精症的生育力低下男性进行抗雌激素治疗的随机试验进行概述，以检验该假设。数据来源包括在线搜索 1966 年至 1994 年间的 MEDLINE 和科学引文索引数据库、扫描已知初步研究和评论文章的参考书目以及联系该领域的专家。经过独立、盲法评估，最初确定的 149 项研究中有 9 项符合纳入标准并被选中。我们独立评估研究质量。对每项研究的结果数据进行汇总和统计总结。结果：抗雌激素治疗的妊娠率略有改善（比值比，1.6；95% 置信区间，0.9 至 2.6）。基于方法学质量的敏感性分析表明，低质量的研究对治疗产生了积极的影响，而高质量的研究则没有观察到任何益处。结论：荟萃分析的结果受到纳入的主要研究质量的影响。从方法论上来说，糟糕的研究往往会夸大治疗效果的总体估计，并可能导致错误的推论。
Background: Traditional and largely qualitative reviews of evidence are now giving way to much more structured systematic overviews that use a quantitative method to calculate the overall effect of treatment. The latter approach is dependent on the quality of primary studies, which may introduce bias if they are of poor methodologic quality.Objective: To test the hypothesis that the inclusion of poor-quality trials in meta-analyses would bias the conclusions and produce incorrect estimates of treatment effect.Methods: An overview of randomized trials of antiestrogen therapy in subfertile men with oligospermia was performed to test the hypothesis. Data sources included online searching of MEDLINE and Science Citation Index databases between 1966 and 1994, scanning the bibliography of known primary studies and review articles, and contacting experts in the field. After independent, blind assessment, nine of 149 originally identified studies met the inclusion criteria and were selected. We assessed study quality independently. Outcome data from each study were pooled and statistically summarized.Results: There was a marginal improvement in pregnancy rate with antiestrogen treatment (odds ratio, 1.6; 95% confidence interval, 0.9 to 2.6). Sensitivity analyses on the basis of methodologic quality demonstrated that poor-quality studies produced a positive effect with treatment, whereas no benefit was observed with high-quality studies.Conclusions: The results of a meta-analysis are influenced by the quality of the primary studies included. Methodologically, poor studies tend to exaggerate the overall estimate of treatment effect and may lead to incorrect inferences.