Objective Cluster randomised trial (CRT) investigators face challenges in seeking informed consent from individual patients (cluster members). This study examined associations between reporting of patient consent in healthcare CRTs and characteristics of these trials.

Study design Consent practices and study characteristics were abstracted from a random sample of 160 CRTs performed in primary or hospital care settings that were published from 2000 to 2008. Multivariable logistic regression was used to examine associations between reporting of patient consent and methodological characteristics, as well as publication features such as date and journal of publication.

Results 82 (53.8%) of 160 studies reported obtaining informed consent from individual patients. Reporting of patient consent was independently and positively associated with: smaller cluster size, the evaluation of experimental interventions targeted at patients, data collection from individual patients, publication later than 2004 and publication in higher-impact journals.

Conclusions Reporting of consent practices in published CRTs should be improved. Consent practices in published CRTs appear to be related to the type of interventions under study, as well as journal impact and trends in research ethics practices. These findings will inform best practices in trial conduct and ethics review, remediation of errors in consent practices and ethics review and the development of regulatory guidance for CRTs.