Japan's contribution to clinical research in gastroenterology and hepatology

Background. Although Japan's contributions to several biomedical fields have already been reported, little is known about Japan's contribution to gastroenterology and hepatology. Methods. Original articles published in 1991 through 2000 in highly reputed journals in the field of gastroenterology and hepatology were retrieved from the MEDLINE database. The number of articles having an affiliation with a Japanese institution was counted in total, and the number for each journal was also counted. Japan's share of articles regarding clinical trials and randomized controlled trials (RCTs) in this field was also determined, along with the trend over the past decade. Results. Japan's share of articles in this field was 10.6%, ranking third in the world, following the United States (35.1%) and the United Kingdom (11.5%). Japan's share of articles went up significantly as a whole (P = 0.01), while the share for RCTs showed no significant change (P = 0.57) during this period of time. Conclusions. Japan's contribution to the field of gastroenterology and hepatology is, in general, acceptable compared with that of other counties, but the contribution for RCTs not satisfactory.