Manuscripts based on the same database

If editors receive manuscripts from separate research groups or from the same group analyzing the same data set（for example,from a public database,or systematic reviews or meta-analyses of the same evidence）,the manuscripts should be considered independently because they may differ in their analytic methods,conclusions,or both.If the data interpretation and conclusions are similar,it may be reasonable although not mandatory for editors to give preference to the manuscript submitted first.Editors might consider publishing more than one manuscript that overlap in this way because different analytical approaches may be complementary and equally valid,but manuscripts based upon the same dataset should add substantially to each other to warrant consideration for publication as separate papers,with appropriate citation of previous publications from the same dataset to allow for transparency.

Secondary analyses of clinical trial data should cite any primary publication,clearly state that it contains secondary analyses/results,and use the same identifying trial registration number as the primary trial and unique,persistent dataset identifier.

Sometimes for large trials it is planned from the beginning to produce numerous separate publications regarding separate research questions but using the same original participant sample.In this case authors may use the original single trial registration number,if all the outcome parameters were defined in the original registration.If the authors registered several substudies as separate entries in,for example,clinicaltrials.gov,then the unique trial identifier should be given for the study in question.The main issue is transparency,so no matter what model is used it should be obvious for the reader.

如果编辑收到不同研究组或同一研究组分析同一数据集的几篇稿件（例如，来自同一个公共数据库，或对相同证据的系统综述和Meta 分析），每篇稿件均应分别考虑，因为其分析方法、结论，或此两方面均可能有所不同。如果对数据的解释和结论都相似，编辑较为合理的做法是优先发表先投稿的稿件，尽管并非必须这样做。编辑可以考虑发表这类内容有重复的多篇稿件，因为不同的分析手段可能是互补的且同样是正确的。基于相同数据集的稿件应在很大程度上可以互相补充，以使分别发表这些文章具有合理性，并且应恰当地守用先发表的基于相同数据集的文章以保证透明性。

报告对临床试验数据的再次分析应守用初次分析发表的论文，并清楚地说明，报告中包含再次分析及其结果，而且要与首次分析的试验使用同一临床试验注册号和唯一、永久的数据集标识码。

有时候，大型临床试验一开始就计划针对不同研究问题发表多篇论文，但使用的是同样的原始受试者资料。在这种情况下，如果所有结局指标在最初注册时已确定，则作者可使用最初的那个临床试验注册号。如果作者以几个独立子项目分别注册过，比如在ClinicalTrials.gov 注册，则应分别使用针对研究问题的那个项目的临床试验注册号。关键是要透明，不管采用哪种做法，都应使读者清清楚楚。