Threats to scholarly research integrity arising from paper mills: a rapid scoping review.

"Paper mills" are unethical outsourcing agencies proficient in fabricating fraudulent manuscripts submitted to scholarly journals. In earlier years, the activity of such companies involved plagiarism, but their processes have gained complexity, involving the fabrication of images and fake results. The objective of this study is to examine the main features of retracted paper mills' articles registered in the Retraction Watch database, from inception to the present, analyzing the number of articles per year, their number of citations, and their authorship network. Eligibility criteria for inclusion: retracted articles in any language due to paper mill activity. Retraction letters, notes, and notices, for exclusion. We collected the associated citations and the journals' impact factors of the retracted papers from Web of Science (Clarivate) and performed a data network analysis using VOSviewer software. This scoping review complies with PRISMA 2020 statement and main extensions. After a thorough analysis of the data, we identified 325 retracted articles due to suspected operations published in 31 journals (with a mean impact factor of 3.1). These retractions have produced 3708 citations. Nearly all retracted papers have come from China. Journal's impact factor lower than 7, life sciences journals, cancer, and molecular biology topics were common among retracted studies. The rapid increase of retractions is highly challenging. Paper mills damage scientific research integrity, exacerbating fraud, plagiarism, fake images, and simulated results. Rheumatologists should be fully aware of this growing phenomenon.