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The Impact of Cardiovascular Disease Prevalence on Women's Enrollment in Landmark Randomized Cardiovascular Trials: A Systematic Review

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Abstract

Many studies have demonstrated that women are substantially underrepresented in cardiovascular trials, but few have considered that women develop cardiovascular disease at older ages than men. The extent to which observed gender enrollment inequalities persist after accounting for age-gender differences in disease prevalence is unknown. The purpose of the study was to compare observed rates of women participating in cardiovascular clinical trials with expected rates of female participation based on age- and gender-specific population disease prevalence. Publications between 1997 and 2009 in the three leading medical journals were included to calculate observed women's enrollment rates. Population-based data in Canada were used to determine the expected enrollment rates of women. Multicenter, randomized cardiovascular clinical trials that enrolled both men and women were analyzed. Two reviewers independently extracted data on women's enrollment and important clinical trial characteristics. The female enrollment rate was 30% in the included 325 trials, which ranged from 27% in trials of coronary artery disease, 27% in heart failure, 31% in arrhythmia, to 45% in primary prevention. Increased female enrollment correlated strongly with increasing age at recruitment in cardiovascular clinical trials (P < 0.001). After accounting for age- and gender-specific differences in disease prevalence, gaps in female enrollment were much lower than the expected enrollment rates estimated by 5% in coronary artery disease, 13% in heart failure, 9% in arrhythmia, and 3% in primary prevention. Only cardiovascular trials were evaluated in our study. Female underrepresentation in cardiovascular clinical trials is smaller than conventionally believed after accounting for age- and gender-specific population disease prevalence. Our findings suggest that greater representation of women in cardiovascular clinical trials can be achieved through the recruitment of older populations.

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Funding/Support

This analysis of the study was funded in part by a Canadian Institutes of Health Research (CIHR) operating grant—MOP 102487. Drs. Tsang and Wijeysundera are supported by CIHR Fellowship Awards. Dr. Alter is supported by a Career Investigator Award from the Heart and Stroke Foundation of Ontario. Dr. Ko is supported by a CIHR New Investigator Award.

Role of the Sponsors

The results and conclusions are those of the authors, and should not be attributed to any of the funding or sponsoring agencies. The design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript were made independent of the funding agencies.

Conflict of Interest

None disclosed.

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Authors and Affiliations

  1. University of Chicago Medical Center, Chicago, IL, USA

    Wendy Tsang MD

  2. Institute for Clinical Evaluative Sciences, G-106, 2075 Bayview Avenue, Toronto, ON, Canada, M4N 3M5

    David A. Alter MD, Tony Zhang BSc & Dennis T. Ko MD, MSc

  3. Division of Cardiology, St Michael’s Hospital, Toronto, ON, Canada

    David A. Alter MD

  4. Department of Medicine, University of Toronto, Toronto, ON, Canada

    David A. Alter MD, Harindra C. Wijeysundera MD & Dennis T. Ko MD, MSc

  5. Schulich Heart Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada

    Harindra C. Wijeysundera MD & Dennis T. Ko MD, MSc

Authors
  1. Wendy Tsang MD
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  2. David A. Alter MD
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  3. Harindra C. Wijeysundera MD
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  4. Tony Zhang BSc
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  5. Dennis T. Ko MD, MSc
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Corresponding author

Correspondence to Dennis T. Ko MD, MSc.

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Tsang, W., Alter, D.A., Wijeysundera, H.C. et al. The Impact of Cardiovascular Disease Prevalence on Women's Enrollment in Landmark Randomized Cardiovascular Trials: A Systematic Review. J GEN INTERN MED 27, 93–98 (2012). https://doi.org/10.1007/s11606-011-1768-8

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  • DOI: https://doi.org/10.1007/s11606-011-1768-8

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