title: International participation in cardiovascular randomized controlled trials sponsored by the National Heart, Lung, and Blood Institute.
abstract: OBJECTIVE
  The aim of this study was to describe international enrollment and participation in National Institutes of Health (NIH)-sponsored cardiovascular randomized controlled trials (RCTs).
  
  
  BACKGROUND
  RCTs provide the evidence base for major societal guidelines and profoundly influence patient care in the United States. Increased international involvement in clinical trials has been observed, but the rate of international enrollment in NIH-sponsored cardiovascular RCTs has not been described.
  
  
  METHODS
  The NIH registry of clinical trials was searched for phase III or IV cardiovascular RCTs funded by the National Heart, Lung, and Blood Institute. Studies with outcomes of myocardial infarction, stroke, or death published between 1997 and 2009 were included. Rates of international enrollment were obtained from published data or personal communication with corresponding authors.
  
  
  RESULTS
  Twenty-four studies met all inclusion criteria. Nineteen trials including 151,682 patients had international participation (IP), with median IP of 9.5% (range 0% to 100%). Coronary artery disease trials (11 studies) had nearly 50% international enrollment. High-risk trials and trials testing acute interventions tended to have higher rates of IP.
  
  
  CONCLUSIONS
  Cardiovascular RCTs sponsored by the National Heart, Lung, and Blood Institute have substantial rates of international enrollment, particularly coronary artery disease trials. Given questions of applicability and ethical and financial considerations, IP in U.S. clinical trials deserves further scrutiny.
authors.affiliation: Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Esther S H
authors.initials: ES
authors.lastname: Kim
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Carrigan
authors.forename: Venu
authors.initials: V
authors.lastname: Menon
mesh_terms: D002318:Cardiovascular Diseases; D017326:Clinical Trials, Phase III as Topic; D017327:Clinical Trials, Phase IV as Topic; D006801:Humans; D038622:Internationality; D015337:Multicenter Studies as Topic; D054555:National Heart, Lung, and Blood Institute (U.S.); D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic; D012109:Research Support as Topic; D014481:United States