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March 25, 2020

Enrollment of Older Patients, Women, and Racial/Ethnic Minority Groups in Contemporary Acute Coronary Syndrome Clinical Trials: A Systematic Review

Author Affiliations
  • 1Emory Clinical Cardiovascular Research Institute, Emory University School of Medicine, Atlanta, Georgia
  • 2Brigham and Women’s Hospital Heart & Vascular Center, Harvard Medical School, Boston, Massachusetts
  • 3Duke Clinical Research Institute, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina
  • 4Department of Cardiology, Henry Ford Health Systems, Detroit, Michigan
  • 5The Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
  • 6Section editor, JAMA Cardiology
  • 7Ahmanson-UCLA Cardiomyopathy Center, University of California Los Angeles, Los Angeles
  • 8Department of Medicine, University of Mississippi Medical Center, Jackson
JAMA Cardiol. 2020;5(6):714-722. doi:10.1001/jamacardio.2020.0359
Key Points

Question  How representative are contemporary acute coronary syndrome trials with respect to age, sex, and race/ethnicity?

Findings  In this systematic review of 460 acute coronary syndrome clinical trials enrolling 1 067 520 patients, the mean (SD) age was 62.9 (10.7) years (increasing from 62.3 [11.2] years in 2001-2006 to 64.0 [10.4] years in 2013-2018), and the proportion of women enrolled was 26.8% (decreased from 27.8% in 2001-2006 to 24.9% in 2013-2018). The distribution of racial/ethnic groups was reported in 21.5% of trials; in trials with reported data, enrollment of nonwhite patients was 15.0%.

Meaning  Enrollment of older patients has modestly increased over time, but enrollment of women has not, and less than one-fourth of acute coronary syndrome trials report race/ethnicity.


Importance  Although age, sex, and race/ethnicity are important factors when generalizing the findings of clinical trials to routine practice, trends in the representation of these groups in contemporary acute coronary syndrome (ACS) trials are not well defined.

Objective  To characterize the representation of older patients, women, and racial/ ethnic minorities in ACS randomized trials.

Evidence Review  A systemic search was conducted of ACS trials published in 8 major medical journals between January 2001 and December 2018. Overall, 1 067 520 patients from 460 trials were included. Findings were compared with epidemiologic studies of patients with ACS.

Findings  The median number of participants per trial was 711 (interquartile range, 324-2163) and the median number of sites per trial was 21 (interquartile range, 5-73). Overall, 207 trials (45.0%) studied drug therapy, and 210 (45.7%) evaluated procedural interventions. The mean (SD) age of trial participants was 62.9 (10.7) years and increased from 62.3 (11.2) years in 2001-2006 to 64.0 (10.4) years in 2013-2018 (P = .01). The corresponding mean (SD) age was 66.4 (14.8) years in US epidemiologic studies and 70.0 (13.5) years in European epidemiologic studies. The overall proportion of women enrolled was 26.8% and decreased over time, from 27.8% in 2001-2006 to 24.9% in 2013-2018 (P = .21 for trend). The corresponding weighted proportions of women were 38.0% in US epidemiologic studies and 32.0% in European studies. The distribution of racial/ethnic groups was reported in only 99 trials (21.5%). In trials with reported data, 15.0% of the trial participants were nonwhite, which increased from 12.0% in 2001-2006 to 14.0% in 2013-2018. Black patients represented 3.7% of all patients during the entire study time frame, Asian patients represented 9.6%, and Hispanic patients represented 7.8%. Trends in the representation of black patients remained unchanged from 2001-2006 (5.2%) to 2013-2018 (4.9%), while the enrollment of Asian and Hispanic patients increased from 2001-2006 to 2013-2018 (from 1.9% to 10.8% for Asian patients and from 5.4% to 14.5% for Hispanic patients).

Conclusions and Relevance  Older patients and women are underrepresented in contemporary ACS trials compared with epidemiologic studies. Over time, there has been modest improvement in the representation of older patients but not women patients. More than three-quarters of trials did not report race/ethnicity data, with available data suggesting a modest increase in the enrollment of nonwhite patients owing to the enrollment of Asian and Hispanic patients. Enrollment of black patients remained low over time.