Completion, publication, and outcome reporting of registered randomized trials in abdominal surgery: registry-based cohort study.
7 affiliations
- 1Department of General Surgery, Division of Visceral Surgery, Medical University of Vienna, Vienna, Austria.
- 2Department of Surgery, Clarunis University Digestive Health Care Center Basel, University Hospital Basel, Basel, Switzerland.
- 3Department of Surgery, Division of Visceral Surgery, Medical University of Zurich, Zurich, Switzerland.
- 4Department of Surgery, Groene Hart Hospital, Gouda, the Netherlands.
- 5Department of General Surgery, Hôpital Fribourgeois, Fribourg, Switzerland.
- 6Division of Radiation Oncology, Department of Gastrointestinal Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
- 7Usher Institute, The University of Edinburgh, Edinburgh, UK.
Abstract
Background
Abdominal surgery poses unique challenges to the conduct of randomized clinical trials (RCTs). However, trial discontinuation, non-publication, and selective reporting may result in an incomplete picture of the available evidence base. This study assessed the trajectories of RCTs in abdominal surgery from trial registration to the publication and reporting of results.Methods
RCTs in adult abdominal surgery were identified through a systematic search of ClinicalTrials.gov, the EU Clinical Trials Register, and the International Clinical Trials Registry Platform from database inception until 31 January 2018. Corresponding trial publications were identified by searching PubMed, Google Scholar, and Google. Selective reporting was evaluated by examining consistency of primary endpoints and reported P values in published trials.Results
After screening 2654 registry records, 295 trials were deemed eligible for inclusion. Among these, 160 (54%) were reported as completed in trial registries. An elective non-cancer trial population was associated with lower odds of non-completion (odds ratio (OR) 0.46; 95% c.i. 0.27 to 0.78), whereas trials with no reported funding had higher odds of non-completion compared with funded trials (OR 2.05; 95% c.i. 1.16 to 3.66). Among completed trials, a corresponding publication was identified for 119 trials (74%). Completed superiority trials with added or modified primary endpoints were more likely to report P values < 0.050 than primary endpoint-unmodified trials (OR 4.28; 95% c.i. 2.23 to 8.22).Conclusion
Nearly half of registered trials are not reported as completed, and a significant proportion of completed trials are not published. Among published trials, discrepancies between registered and published primary outcomes are common. This is consistent with possible selective outcome reporting and evidentiary bias in abdominal surgery, with implications for both guidelines and meta-analytical work.
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BibTeX
@article{narbekovas2026completion,
title = {{Completion, publication, and outcome reporting of registered randomized trials in abdominal surgery: registry-based cohort study.}},
author = {Klaudia Narbekovas and Christoph Kuemmerli and Sandro Huegli and Jasper P Sijberden and Lukas W Widmer and Oliver Strobel and Max F Stauffer and Ethan B Ludmir and Carl-Stephan Leonhardt},
journal = {BJS open},
year = {2026},
month = sep,
doi = {10.1093/bjsopen/zrag160},
url = {https://europepmc.org/article/MED/42925089},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Completion, publication, and outcome reporting of registered randomized trials in abdominal surgery: registry-based cohort study.
AU - Klaudia Narbekovas
AU - Christoph Kuemmerli
AU - Sandro Huegli
AU - Jasper P Sijberden
AU - Lukas W Widmer
AU - Oliver Strobel
AU - Max F Stauffer
AU - Ethan B Ludmir
AU - Carl-Stephan Leonhardt
PY - 2026
DA - 2026/09/01
JO - BJS open
DO - 10.1093/bjsopen/zrag160
UR - https://europepmc.org/article/MED/42925089
AB - Background Abdominal surgery poses unique challenges to the conduct of randomized clinical trials (RCTs). However, trial discontinuation, non-publication, and selective reporting may result in an incomplete picture of the available evidence base. This study assessed the trajectories of RCTs in abdominal surgery from trial registration to the publication and reporting of results.Methods RCTs in adult abdominal surgery were identified through a systematic search of ClinicalTrials.gov, the EU Clinical Trials Register, and the International Clinical Trials Registry Platform from database inception until 31 January 2018. Corresponding trial publications were identified by searching PubMed, Google Scholar, and Google. Selective reporting was evaluated by examining consistency of primary endpoints and reported P values in published trials.Results After screening 2654 registry records, 295 trials were deemed eligible for inclusion. Among these, 160 (54%) were reported as completed in trial registries. An elective non-cancer trial population was associated with lower odds of non-completion (odds ratio (OR) 0.46; 95% c.i. 0.27 to 0.78), whereas trials with no reported funding had higher odds of non-completion compared with funded trials (OR 2.05; 95% c.i. 1.16 to 3.66). Among completed trials, a corresponding publication was identified for 119 trials (74%). Completed superiority trials with added or modified primary endpoints were more likely to report P values < 0.050 than primary endpoint-unmodified trials (OR 4.28; 95% c.i. 2.23 to 8.22).Conclusion Nearly half of registered trials are not reported as completed, and a significant proportion of completed trials are not published. Among published trials, discrepancies between registered and published primary outcomes are common. This is consistent with possible selective outcome reporting and evidentiary bias in abdominal surgery, with implications for both guidelines and meta-analytical work.
SN - 2474-9842
ER -