Study Finds Women and Minorities Are Under-Represented in Trials
August 3, 2009—The Society for Vascular Surgery announced that a study published by Andrew W. Hoel, MD, et al in the Journal of Vascular Surgery found that enrollment demographics published in many vascular surgery randomized control trials (RCTs) in the United States under-represent women as well as race or ethnic minorities (2009;50:349–354). These groups of patients are generally under-reported in trials for aortic aneurysms, carotid artery stenosis, and peripheral artery disease.
According to the Society for Vascular Surgery, the retrospective study was composed of United States-based RCTs from 1983 through 2007 and focused on three broadly defined vascular procedures: aortic aneurysm repair (AAR), carotid revascularization (CR), and lower extremity revascularization (LER).
The investigators collected and analyzed data with regard to gender and ethnicity, study parameters, funding source, and geographic region. The Nationwide Inpatient Sample (NIS) database was also analyzed to obtain group-specific procedure frequency as an estimate of procedure frequency in the general population. Of 77 studies reviewed by the investigators, 52 met their inclusion criteria.
The investigators found that only 85% of those 52 studies reported gender and 21% reported ethnicity. Reporting of ethnicity was strongly associated with larger (more than 280 subjects) multicenter and government-funded trials. Women were disproportionately under-represented in RCTs for all procedure categories: AAR, 9% versus 21.5%; CR, 30% versus 42.9%; and LER, 22.4% versus 41.3%. Minorities were under-represented in AAR studies (6% vs 10.7%) and CR studies (6.9% vs 9.5%), while they were over-represented in LER studies (26% vs 21.8%).
Investigator Louis L. Nguyen, MD, noted that minority ethnicity and female gender are particularly under-reported and under-represented in small, nongovernment-funded and single-center trials; and therefore, the ability to generalize some trial results may not be applicable to these populations. He noted that RCTs are considered to be the strongest level of evidence in evidence-based medicine because random assignment of patients in one of two treatment groups allows for unbiased analysis, and also because they have to meet strict scientific, ethical, and regulatory standards in order to yield meaningful results while preserving patient safety.
"We recognize that under-representation of some demographic groups in RCTs may be an unintentional or unavoidable consequence of conducting safe, timely, and much-needed trials," commented Dr. Nguyen. "Though well-studied in other fields, balanced enrollment of patients with relevant demographic characteristics in vascular surgery RCTs is not well-known. Our findings call into question the applicability of current evidence-based medicine for women and race/ethnic minorities with vascular disease."