Use of mifepristone to treat endometriosis: a review of clinical trials and trial-like studies conducted in China.

China was the first country in the world that approved mifepristone (RU-486) for abortion. A total of 6 years after the report published in the Western world indicated that mifepristone may also be effective in treating endometriosis, the first paper on the same topic was published in China in 1997. Since then, over 160 studies on this topic have been published in China. We retrieved 104 papers on clinical trials and trial-like studies conducted in China evaluating the use of mifepristone to treat endometriosis that were published in the last 11 years. We found that the quality of these studies is well below an acceptable level, making it difficult to judge whether mifepristone is truly efficacious. There are intriguing signs that these studies, as a whole, have serious anomalies. The areas that are glaringly deficient are informed consent, choice of outcome measures, the evaluation of outcome measures, data analysis and randomization. The uniformly low quality is disquieting, given the large quantity of studies, the enormous amount of resource and energy put into these studies and, above all, the weighty issue of treatment efficacy that concerns each and every patient with endometriosis. Equally disquieting are the low-quality repetition, the absence of a critical, systematic review on the subject, the lack of suggestions for multicenter clinical trials and the seemingly unnecessary duplication of clinical trials without due informed consent. In view of this, it may be time to institute changes in attitude and practice, and to change education and training programs in the methodology of clinical trials in obstetrics and gynecology research in China.