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Outcome reporting bias in Cochrane systematic reviews: a cross-sectional analysis.
BMJ Open ( IF 2.4 ) Pub Date : 2020-03-16 , DOI: 10.1136/bmjopen-2019-032497
Kieran Shah 1 , Gregory Egan 2 , Lawrence Nichoe Huan 2 , Jamie Kirkham 3 , Emma Reid 4 , Aaron M Tejani 5
BMJ Open ( IF 2.4 ) Pub Date : 2020-03-16 , DOI: 10.1136/bmjopen-2019-032497
Kieran Shah 1 , Gregory Egan 2 , Lawrence Nichoe Huan 2 , Jamie Kirkham 3 , Emma Reid 4 , Aaron M Tejani 5
Affiliation
BACKGROUND
Discrepancies in outcome reporting (DOR) between protocol and published studies include inclusions of new outcomes, omission of prespecified outcomes, upgrade and downgrade of secondary and primary outcomes, and changes in definitions of prespecified outcomes. DOR can result in outcome reporting bias (ORB) when changes in outcomes occur after knowledge of results. This has potential to overestimate treatment effects and underestimate harms. This can also occur at the level of systematic reviews when changes in outcomes occur after knowledge of results of included studies. The prevalence of DOR and ORB in systematic reviews is unknown in systematic reviews published post-2007.
OBJECTIVE
To estimate the prevalence of DOR and risk of ORB in all Cochrane reviews between the years 2007 and 2014.
METHODS
A stratified random sampling approach was applied to collect a representative sample of Cochrane systematic reviews from each Cochrane review group. DOR was assessed by matching outcomes in each systematic review with their respective protocol. When DOR occurred, reviews were further assessed if there was a risk of ORB (unclear, low or high risk). We classified DOR as a high risk for ORB if the discrepancy occurred after knowledge of results in the systematic review.
RESULTS
150 of 350 (43%) review and protocol pairings contained DOR. When reviews were further scrutinised, 23% (35 of 150) of reviews with DOR contained a high risk of ORB, with changes being made after knowledge of results from individual trials.
CONCLUSIONS
In our study, we identified just under a half of Cochrane reviews with at least one DOR. Of these, a fifth were at high risk of ORB. The presence of DOR and ORB in Cochrane reviews is of great concern; however, a solution is relatively simple. Authors are encouraged to be transparent where outcomes change and to describe the legitimacy of changing outcomes in order to prevent suspicion of bias.
中文翻译:
Cochrane系统评价的结果报告偏倚:横断面分析。
背景方案和已发表的研究之间的结果报告(DOR)中的差异包括新结果的纳入,省略了预定结果,次要和主要结果的升级和降级以及预定结果的定义发生了变化。当了解结果后发生结果变化时,DOR可能导致结果报告偏差(ORB)。这有可能高估治疗效果而低估危害。当对纳入研究的结果有所了解后,如果结果发生变化,这也可能发生在系统评价的水平。DOR和ORB在系统评价中的流行程度在2007年后发布的系统评价中是未知的。目的评估2007年至2014年之间所有Cochrane评价中DOR的患病率和ORB风险。方法采用分层随机抽样方法,从每个Cochrane评价组收集Cochrane系统评价的代表性样本。通过将每个系统评价中的结果与各自的方案相匹配来评估DOR。当发生DOR时,将进一步评估是否存在ORB风险(不清楚,低风险或高风险)。如果在系统评审了解结果后出现差异,我们将DOR归类为ORB的高风险。结果350个试验中有150个(43%)评估和方案配对包含DOR。当进一步审查审查时,DOR审查中有23%(150份中的35份)存在ORB的高风险,在了解了各个试验的结果后才进行更改。结论在我们的研究中,我们发现大约一半的Cochrane评价具有至少一个DOR。这些,五分之一的人患ORB的风险很高。在Cochrane审查中存在DOR和ORB引起了极大关注。但是,解决方案相对简单。鼓励作者在结果改变时保持透明,并描述改变结果的合法性,以防止怀疑偏见。
更新日期:2020-03-16
中文翻译:
![](https://scdn.x-mol.com/jcss/images/paperTranslation.png)
Cochrane系统评价的结果报告偏倚:横断面分析。
背景方案和已发表的研究之间的结果报告(DOR)中的差异包括新结果的纳入,省略了预定结果,次要和主要结果的升级和降级以及预定结果的定义发生了变化。当了解结果后发生结果变化时,DOR可能导致结果报告偏差(ORB)。这有可能高估治疗效果而低估危害。当对纳入研究的结果有所了解后,如果结果发生变化,这也可能发生在系统评价的水平。DOR和ORB在系统评价中的流行程度在2007年后发布的系统评价中是未知的。目的评估2007年至2014年之间所有Cochrane评价中DOR的患病率和ORB风险。方法采用分层随机抽样方法,从每个Cochrane评价组收集Cochrane系统评价的代表性样本。通过将每个系统评价中的结果与各自的方案相匹配来评估DOR。当发生DOR时,将进一步评估是否存在ORB风险(不清楚,低风险或高风险)。如果在系统评审了解结果后出现差异,我们将DOR归类为ORB的高风险。结果350个试验中有150个(43%)评估和方案配对包含DOR。当进一步审查审查时,DOR审查中有23%(150份中的35份)存在ORB的高风险,在了解了各个试验的结果后才进行更改。结论在我们的研究中,我们发现大约一半的Cochrane评价具有至少一个DOR。这些,五分之一的人患ORB的风险很高。在Cochrane审查中存在DOR和ORB引起了极大关注。但是,解决方案相对简单。鼓励作者在结果改变时保持透明,并描述改变结果的合法性,以防止怀疑偏见。