Nolan Sarah Jane, Hambleton Ian, Dwan Kerry
Department of Biostatistics, University of Liverpool, Liverpool, United Kingdom.
Cochrane Cystic Fibrosis and Genetic Disorders Group, Liverpool, United Kingdom.
PLoS One. 2016 Jul 13;11(7):e0159014. doi: 10.1371/journal.pone.0159014. eCollection 2016.
Systematic reviews of treatment interventions in stable or chronic conditions often require the synthesis of clinical trials with a cross-over design. Previous work has indicated that methodology for analysing cross-over data is inadequate in trial reports and in systematic reviews assessing trials with this design.
We assessed systematic review methodology for synthesising cross-over trials among Cochrane Cystic Fibrosis and Genetic Disorders Group reviews published to July 2015, and assessed the quality of reporting among the cross-over trials included in these reviews.
We performed data extraction of methodology and reporting in reviews, trials identified and trials included within reviews.
We reviewed a total of 142 Cochrane systematic reviews including 53 reviews which synthesised evidence from 218 cross-over trials. Thirty-three (63%) Cochrane reviews described a clear and appropriate method for the inclusion of cross-over data, and of these 19 (56%) used the same method to analyse results. 145 cross-over trials were described narratively or treated as parallel trials in reviews but in 30 (21%) of these trials data existed in the trial reports to account for the cross-over design. At the trial level, the analysis and presentation of results were often inappropriate or unclear, with only 69 (32%) trials presenting results that could be included in meta-analysis.
Despite development of accessible, technical guidance and training for Cochrane systematic reviewers, statistical analysis and reporting of cross-over data is inadequate at both the systematic review and the trial level. Plain language and practical guidance for the inclusion of cross-over data in meta-analysis would benefit systematic reviewers, who come from a wide range of health specialties. Minimum reporting standards for cross-over trials are needed.
对稳定或慢性疾病治疗干预措施的系统评价通常需要综合采用交叉设计的临床试验。以往的研究表明，在试验报告以及评估采用该设计的试验的系统评价中，分析交叉数据的方法并不充分。
我们评估了截至2015年7月发表的Cochrane囊性纤维化和遗传疾病小组评价中综合交叉试验的系统评价方法，并评估了这些评价中纳入的交叉试验的报告质量。
我们对评价、所识别的试验以及评价中纳入的试验的方法和报告进行了数据提取。
我们共检索了142篇Cochrane系统评价，其中53篇评价综合了来自218项交叉试验的证据。33篇（63%）Cochrane评价描述了纳入交叉数据的清晰且合适的方法，其中19篇（56%）采用相同方法分析结果。145项交叉试验在评价中以叙述方式描述或被当作平行试验处理，但在这些试验报告中，有30项（21%）试验存在可说明交叉设计的数据。在试验层面，结果的分析和呈现往往不恰当或不清晰，仅有69项（32%）试验呈现了可纳入荟萃分析的结果。
尽管已为Cochrane系统评价员制定了便于获取的技术指南和培训，但在系统评价和试验层面，交叉数据的统计分析和报告均不充分。为将交叉数据纳入荟萃分析提供通俗易懂的语言和实用指南，将使来自广泛健康专业领域的系统评价员受益。需要制定交叉试验的最低报告标准。
