Non-publication and delayed publication of randomized trials on vaccines: a survey

Abstract

Objective To evaluate the extent of non-publication or delayed publication of registered randomized trials on vaccines, and to investigate potential determinants of delay to publication. Design Survey.Data sources Trials registry websites, Scopus, PubMed, Google. Main outcome measures Publication status of trial results and time from completion to publication in peer reviewed journals. Study selectionData synthesis Cox proportional hazards regression was used to evaluate potential predictors of publication delay. ResultsWe analysed 384 trials (85% sponsored by industry). Of 355 trials (404 758 participants) that were completed, 176 (n=151 379) had been published in peer reviewed journals. Another 42 trials (total sample 62 765) remained unpublished but reported results in ClinicalTrials.gov. The proportion of trials published 12, 24, 36, and 48 months after completion was 12%, 29%, 53%, and 73%, respectively. Including results posted in ClinicalTrials.gov, 48 months after study completion results were available for 82% of the trials and 90% of the participants. Delay to publication between non-industry and industry sponsored trials did not differ, but non-industry sponsored trials were 4.42-fold (P=0.008) more likely to report negative or mixed findings. Negative results were reported by only 2% of the published trials.Conclusions Most vaccine trials are published eventually or the results posted in ClinicalTrials.gov, but delays to publication of several years are common. Actions should focus on the timely dissemination of data from vaccine trials to the public.

Assessing the Eventual Publication of Clinical Trial Abstracts Submitted to a Large Annual Oncology Meeting

“…We found that the clinical trial data from 75% of abstracts reporting randomized trials and from 54% of those describing nonrandomized trials were published by March 2015, a statistically significant difference (p , .001). Our 75% rate of publication for abstracts reporting randomized trials in the ASCO database from 2009-2011 is similar to the 56%-91% reported by others who assessed rates of publication of randomized or large trials [1,9,[22][23][24][25][26][27]. Our finding that clinical data from only 54% of abstracts reporting on nonrandomized trials had been published 4-6 years after their ASCO submissions is consistent with the 56%-74% reported by others 5-7.5 years after publication of the abstract [9,10].…”