Global Disparities in Vascular Research: A Cross-National Analysis of Varicose Vein Trials

Developing countries bear a disproportionate burden of global cardiovascular mortality, yet contribute minimally to vascular research output. This study quantifies these disparities through a focused analysis of varicose vein clinical trials, a condition selected for its global prevalence and accessibility to basic surgical care. A systematic search of Medline, Embase, and the Cochrane Library identified clinical trials on varicose veins published over a five-year period. Studies were classified by country using the UN Human Development Index (HDI), and output was analyzed in relation to national gross domestic product (GDP) and population size. Statistical comparisons between developed and developing countries were performed using independent samples t-tests, Mann-Whitney U tests, and Spearman correlation coefficients. A total of 252 eligible studies from 35 countries were analyzed. Developed nations contributed 73% of the trials, producing one study per 7.5 million people compared to one per 52 million in developing countries (p<0.0001). GDP-normalized output revealed no significant difference between groups, suggesting comparable proportional economic investment. Strong correlations were found between research output and GDP, particularly in developing countries (ρ=0.93, p=0.003), whereas population size showed weaker associations. The findings reveal that while economic scale predicts research output, population-adjusted analysis uncovers deeper systemic barriers in developing countries. Addressing these disparities requires targeted investment in research infrastructure, capacity building, and international collaboration to foster equitable knowledge production in global vascular health.