Xie, Guozhan

Background and Objective: The published cardiology literature is critical for scientific communication, and we sought to determine if the published clinical cardiology evidence base has evolved over time. Methods: We evaluated the cardiology related publications in the medical journals (M) JAMA (J) and the New England Journal of Medicine (N) and all publications by the specialty journals (CA) Circulation (Ci) and the European Heart Journal (E) in 2000, 2010, and 2020 and added 2001, 2011, and 2021 for JAMA to account for potential annual variability. Results: Publication information is shown in the graph. For the M journals there has been an increase in the percentage of randomized controlled trials (RCT). For the CA journals there has been a significant decrease in single center studies (Si) and a proportionate increase in reanalysis (Re) of data whether from subanalysis of an RCT, registry, or meta-analysis. For CA journals there has been an increase in the size of clinical studies mainly due to the use of larger datasets from registries or claims (Ci: 2000: 4,500/study; 2010: 9,298/study; 2020: 258,725/study and E: 2000: 2,282/study; 2010: 12,652/study; 2020: 249,388/study). CA journals have an increased of studies with patients from multiple continents (Ci: 2000: 5.5%; 2010: 13%; 2020: 35% and E: 2000: 7%; 2010: 14.8%; 2020: 18.8%). There has been an increase in the percentage of clinical studies with documentation of different populations by region or color (In 2020, 58% for all Ci articles and 52% for US and multicontinental EHJ articles), although the number of nonwhites remains small in most studies unless the study was specifically addressing disparities in care. Conclusions: Over the last two decades, the published evidence base has changed with more RCT in the Med journals and more studies that reanalyze large datasets in CA journals. Published studies are now larger, more likely to involve multiple continents, and document population details.