Characterization changes and research waste in randomized controlled trials of global bariatric surgery over the past 20 years: cross-sectional study.

Background: The results of several large randomized controlled trials (RCTs) have changed the clinical practice of bariatric surgery. However, the characteristics of global RCTs of bariatric surgery have not been reported internationally and whether there was research waste in these RCTs is unknown.

Methods: Search ClinicalTrials.gov for bariatric surgery RCTs registered between January 2000 and December 2022 with the keywords 'Roux-en-Y gastric-bypass' and 'Sleeve Gastrectomy'. The above analysis was conducted in January 2023.

Results: A total of 326 RCTs were included in this study. The number of RCTs registered for sleeve gastrectomy and gastric bypass surgery increased year by year globally. Europe has always accounted for the largest proportion, Asia has gradually increased, and North America has decreased. A total of 171 RCTs were included in the analysis of waste, of which 74 (43.8%) were published. Of the 74 published RCTs, 37 (37/74, 50.0%) were judged to be adequately reported and 36 (36/74, 48.6%) were judged to have avoidable design defects. In the end, 143 RCTs (143/171, 83.6%) had at least one research waste. Body weight change as the primary endpoint (OR: 0.266, 95% CI: 0.103-0.687, P =0.006) and enrolment greater than 100 (OR: 0.349, 95% CI: 0.146-0.832, P =0.018) were independent protective factors for research waste.

Conclusions: This study for the first time describes the characteristic changes of the mainstream RCT of bariatric surgery globally in the last 20 years and identifies a high research waste burden and predictive factor in this area, which provides reference evidence for carrying out bariatric surgery RCTs more rationally.