Daly Anna, Treweek Shaun, Shiely Hayes Genevieve, Shiely Frances
TRAMS (Trials Research and Methodologies Unit), HRB Clinical Research Facility, University College Cork, Cork, Ireland.
HRB Trials Methodology Research Network (TMRN), University College Cork, Cork, Ireland.
Trials. 2025 Mar 29;26(1):110. doi: 10.1186/s13063-025-08747-4.
We previously published a study examining the risk of bias of a random selection of Cochrane systematic reviews. The purpose of our current study is to reassess the risk of bias of a cohort of Cochrane reviewed trials to see if our reassessment differs from the original Cochrane assessment and to determine whether the funder, having methodological support, or involving a statistician affected the risk of bias.
We extracted data from 140 of 159 included trials from three countries, the UK, Canada, and Ireland, in our original cohort. The 19 remaining trials were excluded for a variety of reasons. We recorded the number of participants in the trial, the funder, if a statistician was involved in the trial, if there was any methodological support from a trials unit or clinical research facility, the sponsor, and whether the sponsor was involved in the design or conduct of the trial. The risk of bias of the 140 trials was re-assessed using the same tool as that used by the Cochrane authors.
Our judgement of overall high risk of bias was broadly consistent with the original Cochrane authors. The proportion of high risk of bias trials remained more or less where it was at 55%, but the proportion of low risk of bias trials increased from 9 to 16%. The proportion of unclear risk of bias trials changed accordingly. Compared to the original assessments, we judged more studies to be low risk of bias across all domains. The greatest variation was in the two blinding categories (participants and personnel; outcome assessor) and 'other bias'.
More than half of trials in our UK, Canada, and Ireland cohort were at high risk of bias highlighting significant challenges in ensuring the integrity and reliability of research findings. Addressing bias in clinical trials is essential to uphold the credibility of scientific research and to ensure that healthcare interventions are based on sound evidence, ultimately improving patient outcomes.
我们之前发表了一项研究，考察了随机选取的Cochrane系统评价的偏倚风险。我们当前研究的目的是重新评估一组Cochrane综述试验的偏倚风险，以查看我们的重新评估是否与Cochrane的原始评估不同，并确定资助者、获得方法学支持或有统计学家参与是否会影响偏倚风险。
我们从原始队列中来自英国、加拿大和爱尔兰这三个国家的159项纳入试验中的140项提取了数据。其余19项试验因各种原因被排除。我们记录了试验中的参与者数量、资助者、试验中是否有统计学家参与、试验单位或临床研究机构是否提供了任何方法学支持、申办者，以及申办者是否参与了试验的设计或实施。使用与Cochrane作者相同的工具对这140项试验的偏倚风险进行了重新评估。
我们对总体高偏倚风险的判断与Cochrane的原始作者大致一致。高偏倚风险试验的比例大致保持在55%，但低偏倚风险试验的比例从9%增加到了16%。偏倚风险不明确试验的比例相应变化。与原始评估相比，我们认为所有领域中更多的研究为低偏倚风险。最大的差异在于两个盲法类别（参与者和人员；结果评估者）以及“其他偏倚”。
我们英国、加拿大和爱尔兰队列中超过一半的试验存在高偏倚风险，这凸显了在确保研究结果的完整性和可靠性方面的重大挑战。解决临床试验中的偏倚对于维护科学研究的可信度以及确保医疗保健干预基于可靠证据至关重要，最终可改善患者结局。
