Full publication of preprint articles in prevention research: an analysis of publication proportions and results consistency

There is concern that preprint articles will lead to an increase in the amount of scientifically invalid work available. The objectives of this study were to determine the proportion of prevention preprints published within 12 months, the consistency of the effect estimates and conclusions between preprint and published articles, and the reasons for the nonpublication of preprints. Of the 329 prevention preprints that met our eligibility criteria, almost half (48.9%) were published in a peer-reviewed journal within 12 months of being posted. While 16.8% published preprints showed some change in the magnitude of the primary outcome effect estimate, 4.4% were classified as having a major change. The style or wording of the conclusion changed in 42.2%, the content in 3.1%. Preprints on chemoprevention, with a cross-sectional design, and with public and noncommercial funding had the highest probabilities of publication. The main reasons for the nonpublication of preprints were journal rejection or lack of time. The reliability of preprint articles for evidence-based decision-making is questionable. Less than half of the preprint articles on prevention research are published in a peer-reviewed journal within 12 months, and significant changes in effect sizes and/or conclusions are still possible during the peer-review process.