Reporting of interventions in randomised trials: an audit of journal instructions to authors

A complete description of the intervention in a published trial report is necessary for readers to be able to use the intervention, yet the completeness of intervention descriptions in trials is very poor. Low awareness of the issue by authors, reviewers, and editors is part of the cause and providing specific instructions about intervention reporting to authors and encouraging full sharing of intervention materials is important. We assessed the extent to which: 1) journals' Instructions to Authors provide instructions about how interventions that have been evaluated in a randomised controlled trial (RCT) should be reported in the paper; and 2) journals offer the option of authors providing online supplementary materials.

We examined the web-based Instructions to Authors of 106 journals (the six leading general medical journals, 50 randomly selected journals from the National Library of Medicine's Core Clinical Journals, and 50 randomly selected journals from the remainder of the journal collection indexed by PubMed). To be eligible, each journal must have published at least one randomised trial involving human participants each year from 2008 to 2012. We extracted all information related to the reporting of interventions, reporting of randomised trials in general, and online supplementary materials.

Of the 106 journals' Instructions to Authors, only 15 (14%) specifically mentioned the reporting of interventions and most of these provided non-specific advice such as 'describe essential features'. Just over half (62, 58%) of the journals mentioned the Consolidated Standards of Reporting Trials (CONSORT) statement in their author instructions. Seventy-eight (74%) of the journals' instructions mentioned the option of providing supplementary content online as part of the paper; however, only four of these journals explicitly encouraged or mandated use of this option for providing intervention information or materials.

Most journals' Instructions to Authors do not provide any specific instructions regarding reporting of interventions or encourage authors to provide online supplementary materials to enhance intervention reporting. Journals can help to improve the problem of incomplete intervention reporting by providing specific instructions to authors and peer reviewers about intervention reporting and requiring full intervention descriptions to be provided.