Abstract
Adherence to study registration and reporting best practices is vital to fostering evidence-based medicine. All registered clinical trials on ClinicalTrials.gov conducted in Canada as of 2009 and completed by 2019 were identified. A cross-sectional analysis of those trials assessed prospective registration, subsequent result reporting in the registry, and subsequent publication of study findings. The lead sponsor, phase of study, clinical trial site location, total patient enrollment, number of arms, type of masking, type of allocation, year of completion, and patient demographics were examined as potential effect modifiers to these best practices. A total of 6720 trials were identified. From 2009 to 2019, 59% (n = 3,967) of them were registered prospectively, and 32% (n = 2138) had neither their results reported nor their findings published. Of the 3763 trials conducted exclusively in Canada, 3% (n = 123) met all three criteria of prospective registration, reporting in the registry, and publishing findings. Overall, the odds of having adherence to all three practices concurrently in Canadian trials decrease by 95% when compared with international trials. Canadian clinical trials substantially lacked adherence to study registration and reporting best practices. Knowledge of this widespread non-compliance should motivate stakeholders in the Canadian clinical trial ecosystem to address and continue to monitor this problem.
Background
Publication bias is “the tendency on the part of investigators, reviewers, and editors to submit or accept manuscripts for publication based on the direction or strength of the study findings” (Dickersin 1990). Studies with statistically significant or positive results are more likely to be published than those with statistically non-significant or negative results—this means the dissemination of research findings is a biased process (Stern and Simes 1997; Dubben and Beck-Bornholdt 2005; Song et al. 2010; Dwan et al. 2013). Similarly, studies with positive results were much more likely to be published in a shorter time than studies with indefinite conclusions (Stern and Simes 1997). Publication bias threatens the practice of evidence-based medicine, the validity of meta-analyses, and the reproducibility of a study (Marks‐Anglin and Chen 2020). Under-reporting due to publication bias exaggerates the benefits of treatments and underestimates their harms (McGauran et al. 2010). Ultimately, this is detrimental to the healthcare system, as it wastes resources and puts patients at risk (Moher 1993; Chalmers et al. 2013). Between 1999 and 2007, fewer than half of all trials registered and completed on ClinicalTrials.gov were published (Ross et al. 2009). Between 2010 and 2012, fewer than half of all the registered trials for rare diseases were published within four years of their completion (Rees et al. 2019).
