Retraction—Combination treatment of angiotensin-II receptor blocker and angiotensin-converting-enzyme inhibitor in non-diabetic renal disease (COOPERATE): a randomised controlled trial

Abstract

After a letter of concern, 1 Kunz R Wolbers M Glass T Mann JFE The COOPERATE trial: a letter of concern. Lancet. 2008; 371: 1575-1656 Summary Full Text Full Text PDF PubMed Scopus (87) Google Scholar which arose when Regina Kunz and colleagues attempted to include the data from COOPERATE into a meta-analysis, we have now received the conclusions of an institutional investigation into the COOPERATE trial. 2 Nakao N Yoshimura A Morita H Takada M Kayano T Ideura T Combination treatment of angiotensin II receptor blocker and angiotensin-converting-enzyme inhibitor in non-diabetic renal disease (COOPERATE): a randomised controlled trial. Lancet. 2003; 361: 117-124 Summary Full Text Full Text PDF PubMed Scopus (954) Google Scholar The investigation committee led by Yutuka Sanada, the President of Showa University Fujigaoka Hospital, met seven times, questioned the lead author, Naoyuki Nakao, directly, and examined the original medical records of his patients at Gen Gen-Do Kimitsu Hospital, where the trial was conducted. They concluded that contrary to statements in the paper, the trial had not been approved by the ethics committee of Gen Gen-Do Kimitsu Hospital. Also, contrary to the statement on patients' consent, Dr Nakao reposted that he had received verbal consent from patients shortly after the start of the study and written consent only during the study. The involvement of a statistician could not be verified. The committee concluded that the trial was not a double-blind study, because Dr Nakao knew the treatment allocation. In the attempt to assess the validity of the data, a sample of medical records was compared with the data provided by Dr Nakao. The committee concluded that it was unable to prove the authenticity of the data. RETRACTED: Combination treatment of angiotensin-II receptor blocker and angiotensin-converting-enzyme inhibitor in non-diabetic renal disease (COOPERATE): a randomised controlled trialCombination treatment safely retards progression of non-diabetic renal disease compared with monotherapy. However, since some patients reached the combined primary endpoint on combined treatment, further strategies for complete management of progressive nondiabetic renal disease need to be researched. Full-Text PDF The COOPERATE trial: a letter of concernIn the context of a meta-analysis,1 we had reason to take an in-depth look at a study by Naoyuki Nakao and colleagues2 published in The Lancet in 2003. We detected implausibilities of serious concern. Full-Text PDF