Yoshitaka Fujii

As of 2023, 183 of Fujii's research publications have been retracted, and 47 other papers have received an expression of concern. This is reported as the most retractions of scientific papers by a single author.

Yoshitaka Fujii (藤井 善隆, Fujii Yoshitaka) is a Japanese researcher in anesthesiology, who in 2012 was found to have fabricated data in at least 219 scientific papers, setting what is believed to be a record for the number of papers by a single author requiring retractions.

In February 2012, after initial investigations into allegations of scientific misconduct, he was dismissed from his position as associate professor of anesthesiology in the Toho University Faculty of Medicine.

Two analyses of some of Fujii's publications were released in March 2012. On 7 March, Toho University reported finding that although nine of Fujii's publications were about clinical studies described as having been conducted at Ushiku Aiwa General Hospital, the hospital's ethics committee had given Fujii approval for only one study. Following this discovery, eight of the nine papers were retracted for failure to follow established ethical standards for clinical research. On 8 March, Anaesthesia published a report by John Carlisle, a consultant anesthetist in the United Kingdom, on his statistical analysis of the data reported in 168 papers by Fujii. Carlisle used statistical methods to evaluate whether the published distributions of various variables were consistent with the distributions that could be expected to result from random chance. He found that many of the data sets were "extremely unlikely to have arisen by chance", noting that many of the distributions had "likelihoods that are infinitesimally small", citing a calculated probability of 6.78 × 10, or about 1 in 150 million. Accordingly, he recommended that data published by Fujii should be "excluded from meta-analyses or reviews" until such time that the unlikely results could be satisfactorily explained.

In April, the editors of 23 scientific journals made a public request for an investigation of Fujii's research by the seven Japanese institutions named as affiliations in his published papers. A committee of the Japanese Society of Anesthesiologists, headed by Koji Sumikawa of Nagasaki University, undertook an examination of 212 of the 249 papers credited to Fujii. The committee interviewed Fujii's listed co-authors and other people who had been involved with Fujii's research. Committee members also attempted to obtain and review laboratory notebooks, patient records, and other raw data from his studies. On 29 June 2012, the committee reported finding that a total of 172 papers contained fabricated data. Of these, 126 papers were determined to have been "totally fabricated". The report stated: "It is as if someone sat at a desk and wrote a novel about a research idea." The committee found that three of the 212 papers were valid. For 37 of the 212 papers, the committee was unable to determine whether data had been fabricated.

Fujii apparently began publishing falsified data in 1993. The first published allegations of research fraud by Fujii appeared in 2000 in a letter to the editor of the journal Anesthesia & Analgesia by Peter Kranke, Christian Apfel, and others. The letter questioned Fujii's reported findings regarding the effectiveness of granisetron in controlling post-surgical nausea and vomiting, characterizing the data reported in 47 papers as "incredibly nice" and stating "we became skeptical when we realized that side effects were almost always identical in all groups". A paper published by the same group in 2001 in Acta Anaesthesiologica Scandinavica reported "consistent discrepancies" between Fujii's data and other researchers' findings on the efficacy of granisetron. Fujii dismissed the criticisms of his work, insisting that his results were "true" and asking "How much evidence is required to provide adequate proof?" Apfel wrote to the U.S. Food and Drug Administration, the Japanese Pharmaceuticals and Medical Devices Agency, and the Japanese Society of Anesthesiologists to alert them to the possible unreliability of Fujii's results, but did not receive any response. No institutional review of Fujii's research was requested and journals continued to accept new papers submitted by Fujii. The editors of Anesthesia & Analgesia did not follow up on the fraud allegations against Fujii until about 2010, when its editor and the editors of several other journals began a coordinated investigation into the integrity of Fujii's scientific publications after the editor of the journal Anaesthesia voiced new concerns. In March 2012, the editor of Anesthesia & Analgesia acknowledged that the journal's response to the allegations made in 2000 had been "inadequate".

Fujii graduated from Tokai University School of Medicine in 1987 and holds an M.D. degree. He attended the Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, where he majored in anesthesiology and received his Ph.D. in 1991. During his career, he worked at institutions including Tokyo Medical and Dental University, the University of Tsukuba, and Toho University. According to an online CV, he spent two years in Canada as a research fellow at Royal Victoria Hospital, McGill University, before assuming a faculty position at the University of Tsukuba Institute of Clinical Medicine in 1997. He joined the faculty of Toho University in 2005. The main subject of his research publications was clinical trials of medications to treat the nausea and vomiting that often occurs after surgery.