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.
