Geographic representation of trial leaders and collaborators among 414 heart failure randomized controlled trials published in high-impact journals between 2000 and 2020. (A) Geographic representation of 4656 collaborators from each continent by year. (B) Temporal trends in the proportion of trial leaders (first or last authors) and collaborators (authors in any position) outside Europe and North America. There were 828 trial leaders and 4656 trial collaborators represented in the sample. Trends were analysed using the Jonckheere–Terpstra proportion trend test (two-tailed test, α = 0.05). Error bars represent 95% confidence interval.