Clinical trial registry use in minimally invasive surgical oncology systematic reviews and meta-analyses.

Publication bias can arise in systematic reviews when unpublished data are omitted and lead to inaccurate clinical decision making and adverse clinical outcomes. By conducting searches of clinical trial registries (CTRs), researchers can create more accurate systematic reviews and mitigate the risk of publication bias. The aims of this study are: to evaluate CTR use in systematic reviews and meta-analyses within the minimally invasive surgical oncology (MISO) literature; to conduct a search of ClinicalTrials.gov for a subset of reviews to determine if eligible trials exist that could have been used. This is a cross-sectional study of 197 systematic reviews and meta-analyses retrieved from PubMed. Of 137 included studies, 18 (13.1%) reported searching a CTR. Our ClinicalTrials.gov search revealed that of the 25 randomly selected systematic reviews that failed to conduct a trial registry search, 16 (64.0%) would have identified additional data sources. MISO systematic reviews and meta-analyses do not regularly use CTRs in their data collection, despite eligible trials being freely available.

The fragility of randomized trial outcomes underlying management of dyspepsia and Helicobacter pylori infections.

AIM: The fragility index is calculated by changing one outcome event to a nonevent within a trial until the associated P value exceeds 0.05. In this study, we assessed the robustness, risk of bias (RoB), and power of randomized controlled trials that underlie recommendations set forth by the American College of Gastroenterology (ACG) on managing dyspepsia and Helicobacter pylori infections. METHODS: All citations referenced in the guidelines were screened for inclusion criteria. The fragility indexes for eligible trials were then calculated. The likelihood and sources of bias in the included trials were evaluated by the Cochrane 'RoB' Tool 2.0. RESULTS: The median fragility index for the 52 trials was three events. Five studies (9.6%) resulted in a fragility index of 0 when statistical analysis was applied. For the 52 trials, 12 (23.1%) were at a low RoB, 15 (28.8%) had some concerns, and 25 (48.1%) were at a high RoB. High RoB was most commonly due to bias of selection in the reported result (15.5%). CONCLUSION: A median of three events was needed to nullify statistical significance in 52 trials that underpin guideline recommendations on the management of dyspepsia and H. pylori infections. In addition, concerns for RoB were found for these trials.

Is publication bias present in gastroenterological research? An analysis of abstracts presented at an annual congress.

BACKGROUND: Publication bias is the tendency of investigators, reviewers, and editors to submit or accept manuscripts for publication based on their direction or strength of findings. In this study, we investigated if publication bias was present in gastroenterological research by evaluating abstracts at Americas Hepato-Pancreato-Biliary Congresses from 2011 to 2013. METHODS: We searched Google, Google Scholar, and PubMed to locate the published reports of research described in these abstracts. If a publication was not found, a second investigator searched to verify nonpublication. If abstract publication status remained undetermined, authors were contacted regarding reasons for nonpublication. For articles reaching publication, the P value, study design, time to publication, citation count, and journals in which the published report appeared were recorded. RESULTS: Our study found that of 569 abstracts presented, 297 (52.2%) reported a P value. Of these, 254 (85.5%) contained P values supporting statistical significance. The abstracts reporting a statistically significant outcome were twice as likely to reach publication than abstracts with no significant findings (OR 2.10, 95% CI [1.06-4.14]). Overall, 243 (42.7%) abstracts reached publication. The mean time to publication was 14 months and a median time of nine months. CONCLUSION: In conclusion, we found evidence for publication bias in gastroenterological research. Abstracts with significant P values had a higher probability of reaching publication. More than half of abstracts presented from 2011 to 2013 failed to reach publication. Readers should take these findings into consideration when reviewing medical literature.

Assessing quality of randomized trials supporting guidelines for laparoscopic and endoscopic surgery.

BACKGROUND: Recent studies have highlighted the risk of bias and the fragility of results in randomized controlled trials (RCTs). The aim of our study was to evaluate the clinical practice guidelines created by the Society for Gastrointestinal and Endoscopic Surgeons (SAGES) for fragility, statistical power, and risk of bias. MATERIALS AND METHODS: We screened the SAGES clinical practice guideline references for qualifying RCTs. RCTs were assessed for risk of bias using the Cochrane Collaboration Risk of Bias tool 2.0. We used the fragility index and fragility quotient to evaluate the robustness of trial results and conducted a power analysis using G*Power to determine if trials were adequately powered. RESULTS: Twenty-two (40.7%) of the 54 trials that we assessed were rated as having a high risk of bias, 17 (31.5%) were rated as having a low risk of bias, and 15 (27.8%) were rated as having some concerns. The median fragility index was 2.5 (interquartile range 1-7). The median fragility quotient was 0.021 (interquartile range 0.003-0.045). Mean sample size was 108, and the mean loss to follow-up was eight patients. Eight of 33 trials (24.2%) were found to be underpowered according to the sample size used in the primary outcome. CONCLUSIONS: Guidelines created by SAGES are supported by RCTs that are frequently fragile or underpowered or have a high risk of bias. Future RCTs should utilize the Consolidated Standards of Reporting Trials statement, implement strategies to minimize loss to follow-up, and use properly powered sample sizes.