Characteristics and publication discrepancies of foot & ankle surgery-related clinical trials.

Background: Trial registration can provide more reliable study designs, however, the final publications are not exempt from bias. This study aimed to show the characteristics of foot & ankle surgery-related clinical trials registered in ClinicalTrials.gov (CTG) and analyze possible risk factors that can lead to discrepancies between the original trial registry and published results.

Methods: Foot & ankle surgery-related randomized controlled studies registered in CTG with an anticipated completion date until 2018 were extracted. 157 trials were found eligible for final analysis and corresponding publications were investigated through literature databases. Discrepancies between trial registries and published results were analyzed.

Results: 67.5% of trials were registered whether during the trial period or after completion. 46.5% were funded by industry. 54.8% of trials were reported to be completed. The results of 66 (42%) trials were published in a journal. There was a sample size discrepancy in 57.6%, follow-up time discrepancy in 28.8%, primary outcome discrepancy in 45.5%, and inclusion/exclusion criteria discrepancy in 89.4% of registries. Sample size, inclusion/exclusion criteria discrepancies were significantly more in trials funded by industry (p = 0.024, 0.001, 0.037, respectively). Industry-funded studies reported positive results more frequently (p = 0.011).

Conclusion: Only 42% of all registered foot & ankle surgery-related studies had the chance to be published. The majority of studies presented discrepancies in sample size, outcome assessment method, follow-up time, or inclusion/exclusion criteria. Industry-funded studies showed a higher rate of discrepancies and were more inclined towards reporting positive results indicating a risk of bias in assessments.

Level Of Clinical Evidence: Level 3.