Publication Bias in Clinical Trials in Cataract Therapies: Implications for Evidence-Based Decision-Making: Publication Bias in Clinical Trials in Cataract Therapies.

ABSTRACT: Evidence-based decision-making is generally based on published evidence. Therefore, if the published evidence is biased, so will the decision-making. One possible bias is the "positive-results" publication bias. This study attempts to characterize this phenomenon in cataract therapy trials. Studies were categorized as "positive" if their results were congruent with the hypothesis and "negative" if not. Secondary outcomes included the influence of funding source and differences in publication metrics between "positive" and "negative" publications. The US NLM Clinical Trials database was reviewed for cataract trials, yielding 248 trials. Trials with less than 2 treatment arms, less than 5 participants, or insufficient reporting were excluded. Data was collected on intervention, treatment arms, funding type, publication rates, citation rate, and the impact factor/H-index of journals. Of the 132 trials included, there were 69 positive and 63 negative results. Publication rate for positive results (71%) was significantly greater than negative results (17%), (p<0.01), with no significant difference in the other publication metrics. In conclusion, "negative" result trials are published less frequently, but are equally valued, if published. There are implications for evidence-based medicine with these findings.

Publication Bias in Upper Gastrointestinal Oncology Clinical Trials.

PURPOSE: Evidence-based medicine requires evaluation of the medical literature to guide clinical reasoning and treatment recommendations. The presence of publication bias towards exclusion of non-statistically significant clinical trials may be leading to an incomplete evaluation of the literature and cause potentially incomplete guidance for patients. We aimed to compare publication rates and impact of publications of positive and negative outcome clinical trials. METHODS: We queried the US National Library of Medicine Clinical Trials database identifying clinical trials with reported results on the topics of pancreatic, liver, and gastric cancer. A "positive" trial was defined as having a statistically significant difference between the treatment arms, while a "negative" did not. Data collected included termination cause, intervention, funding type, publication rates, and journal characteristics. RESULTS: In total, 535 clinical trials were examined, across all pathologies clinical trials with significant findings for the primary outcome were published at a higher rate (99%) compared to those with non-significant findings (77%) (p < 0.01). Significantly, more studies with significant findings reached at least 80% of their estimated enrollment goal versus non-significant studies, 72% and 53% respectively (p < 0.01). Three of four metrics for impact of publication showed no difference between significant and non-significant studies once they reached publication. CONCLUSION: These findings suggest that clinical trials of three of the most common upper gastrointestinal malignancies have a publication bias towards studies with significant primary outcome findings. This study has implications to the way evidence-based medicine is practiced as the medical literature appears to be failing to capture important data for consideration of clinical decision making.