Retrospective on global pulmonary hypertension clinical trials: 1999-2021

Background: Data are quite sparse on the comprehensive analyses of pulmonary hypertension (PH) clinical trials worldwide. Methods: Information including participating countries (developed or developing), intervention type, trial size, PH categories, sponsorship, study phase, design strategies, and participants' demographic characteristics was extracted from PH trials registered on ClinicalTrials.gov from 1999 to 2021. Results: A total of 203 eligible clinical PH trials were screened, involving 23,402 participants, 67.8% of whom were females. Major clinical trials were designed to test drug interventions (95.6%), sponsored solely by industries in 59.5%, and targeting Group 1 PH patients in 76.3%. A large number of countries participated in PH clinical trials; however, most clinical trials were conducted in developed countries (84.2%). Developing countries were involved in clinical trials with larger sample sizes (P<0.01). Additionally, the differences between developed and developing countries centered on interventions, sponsors, PH groups, and design strategies. Furthermore, developing countries participated in multinational clinical trials with good quality, homogeneity, reliability, and data authenticity. All pediatric participants were diagnosed with Group 1 PH and were only involved in drug intervention trials. Children participated in far fewer clinical trials than adults (P<0.01), and most were enrolled in PH clinical trials in developed countries. Among the entire clinical trial population, younger patients with Group 1 PH had a much higher participation to prevalence ratio (PPR). There was no difference in women's PPRs between developed and developing countries. However, developing countries had higher PPRs for PH Groups I and IV (1.28 vs. 1.22, P<0.01), while developed countries had a lower PPR for Group III (P=0.02). Conclusions: PH is attracting increasing global attention, which is not at the same level of progress in developed and developing countries. Women and children with this disease have unique characteristics and require more attention.