Inadequate reporting of research ethics review and informed consent in cluster randomised trials: review of random sample of published trials

Objectives To investigate the extent to which authors of cluster randomised trials adhered to two basic requirements of the World Medical Association’s Declaration of Helsinki and the International Committee of Medical Journal Editors’ uniform requirements for manuscripts (namely, reporting of research ethics review and informed consent), to determine whether the adequacy of reporting has improved over time, and to identify characteristics of cluster randomised trials associated with reporting of ethics practices.Design Review of a random sample of published cluster randomised trials from an electronic search in Medline.Setting Cluster randomised trials in health research published in English language journals from 2000 to 2008.Study sample 300 cluster randomised trials published in 150 journals.Results 77 (26%, 95% confidence interval 21% to 31%) trials failed to report ethics review. The proportion reporting ethics review increased significantly over time (P