A Review of Published Analyses of Case-Cohort Studies and Recommendations for Future Reporting

The case-cohort study design combines the advantages of a cohort study with the efficiency of a nested case-control study. However, unlike more standard observational study designs, there are currently no guidelines for reporting results from case-cohort studies. Our aim was to review recent practice in reporting these studies, and develop recommendations for the future. By searching papers published in 24 major medical and epidemiological journals between January 2010 and March 2013 using PubMed, Scopus and Web of Knowledge, we identified 32 papers reporting case-cohort studies. The median subcohort sampling fraction was 4.1% (interquartile range 3.7% to 9.1%). The papers varied in their approaches to describing the numbers of individuals in the original cohort and the subcohort, presenting descriptive data, and in the level of detail provided about the statistical methods used, so it was not always possible to be sure that appropriate analyses had been conducted. Based on the findings of our review, we make recommendations about reporting of the study design, subcohort definition, numbers of participants, descriptive information and statistical methods, which could be used alongside existing STROBE guidelines for reporting observational studies.

病例队列研究（case-cohort study）设计兼具队列研究的优势与嵌套式病例对照研究的高效性。然而，与更为常规的观察性研究设计不同，目前尚无针对病例队列研究结果报告的规范指南。本研究旨在梳理当前此类研究的报告现状，并为未来的报告工作制定推荐规范。本研究通过PubMed、Scopus及Web of Knowledge数据库，检索2010年1月至2013年3月期间发表于24种主流医学与流行病学期刊的文献，最终纳入32篇报告病例队列研究的论文。队列亚群（subcohort）的抽样比例中位数为4.1%（四分位间距3.7%~9.1%）。纳入的论文在原始队列与队列亚群的人数描述方式、描述性数据的呈现形式，以及所用统计方法的细节披露程度上均存在较大差异，因此有时难以判断其分析方法是否恰当。基于本次综述的结果，我们针对病例队列研究的报告规范提出推荐建议，涵盖研究设计、队列亚群定义、研究对象人数、描述性信息及统计方法等维度，该推荐可与现有的STROBE观察性研究报告指南结合使用。