title: A review of published analyses of case-cohort studies and recommendations for future reporting.
abstract: 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.
authors: Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
authors: Stephen J
authors: SJ
authors: Sharp
authors: École Nationale de la Statistique et de l'Administration Économique Paris Tech, Paris, France.
authors: Manon
authors: M
authors: Poulaliou
authors: Department of Public Health and Primary Care, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
authors: Simon G
authors: SG
authors: Thompson
authors: Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge, United Kingdom.
authors: Ian R
authors: IR
authors: White
authors: Department of Public Health and Primary Care, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
authors: Angela M
authors: AM
authors: Wood
mesh_terms: D012107:Research Design / Q000592:standards*; D058028:Research Report / Q000592:standards*; D013223:Statistics as Topic