Characteristics and publication status of gastrointestinal endoscopy clinical trials registered in ClinicalTrials.gov

Background and aims This study aimed to examine the fundamental characteristics of gastrointestinal (GI) endoscopy trials and evaluate their publication status. Methods A cross-sectional analysis was performed in the ClinicalTrials.gov database, and then the PubMed, Medline, Google Scholar, and Embase databases were searched. A dataset containing GI endoscopy clinical studies from ClinicalTrials.gov registered until November 24, 2017, was downloaded. Data of observational and interventional studies were extracted and analyzed. Publications in peer-reviewed journals were examined for completed trials, and factors associated with publication were identified. Results A total of 1338 of 253,777 clinical trials were assigned into GI endoscopy, of which 1018 were interventional and 320 were observational studies. Of all the trials, those from the USA comprised the largest percentage ( n = 377, 28.18%). The most common field for registered trials was gastroscopy ( n = 436, 32.6%), followed by colonoscopy ( n = 215, 16.1%), endoscopic ultrasound ( n = 186, 13.9%), endoscopic retrograde cholangiopancreatography ( n = 176, 13.1%), and novel endoscopic procedure ( n = 103, 7.7%). A total of 501 trials were completed before November 25, 2015, 281 (56.1%) of which were published. The median time from study completion to publication was 21 months (interquartile range, 12–32 months). Trials that were comprised of medium sample sizes (150–1000 subjects), conducted in Europe or Asia and other countries, and single or quadruple blinded were more likely to be published. Conclusions GI endoscopy is rapidly evolving in clinical applications. Most clinical trials in GI endoscopy are published promptly. These findings demonstrated that investigators are active in performing and communicating the results of clinical trials in the field of GI endoscopy. In the future, the sample size calculation should be presented in detail in the registration system to maintain trial reporting transparency.