South Asian Representation in Cardiovascular Disease Randomized Controlled Trials: A Systematic Review

Background: One in 4 individuals worldwide is of South Asian ancestry and is therefore at increased risk for cardiovascular disease (CVD). However, South Asian representation in CVD randomized controlled trials (RCTs) is not well known. Objectives: The aim of this systematic review was to measure South Asian representation in CVD RCTs and extract post-randomization primary outcome estimates for this population. Methods: We conducted a systematic review to identify major CVD RCTs published between 2018 and 2022. Each study was manually screened and reviewed to identify South Asian participants and representation rates. The protocol for this systematic review was prospectively registered in PROSPERO (South Asian Representation in Cardiovascular Clinical Trials; CRD42023396522). Results: We included 310 RCTs, representing 1,036,737 total and 32,764 (3.2%) South Asian participants. Most South Asian participants (75.4%) were enrolled in trials in South Asia, and 65.2% were enrolled in a single trial in India. After excluding this trial, South Asian individuals represented 1.1% of total trial participants. South Asian representation was highest in trials studying coronary artery disease (9.0%), whereas no South Asian individuals were identified in trials studying heart failure, cardiac arrest, or valvular heart disease. Post-randomization data were available for 28,197 South Asian individuals, representing 7.3% of all participants with post-randomization data. Conclusions: South Asian individuals are underrepresented in major CVD RCTs, and efforts to extend enrollment initiatives in RCTs to South Asian individuals are urgently needed. The extent to which this underrepresentation is a driver of elevated cardiovascular disease risk merits further study.