Under-representation of women and ethnic minorities in vascular surgery randomized controlled trials

Abstract

Objectives: Gender and ethnicity are factors affecting the incidence and severity of vascular disease as well as subsequent treatment outcomes. Although well studied in other fields, balanced enrollment of patients with relevant demographic characteristics in vascular surgery randomized controlled trials (RCTs) is not well known. This study describes the reporting of gender and ethnicity data in vascular surgery RCTs and analyzes whether these studies adequately represent our diverse patient population.

Methods: We conducted a retrospective review of United States-based RCTs from 1983 through 2007 for three broadly defined vascular procedures: aortic aneurysm repair (AAR), carotid revascularization (CR), and lower extremity revascularization (LER). Included studies were examined for gender and ethnicity data, study parameters, funding source, and geographic region. The Nationwide Inpatient Sample (NIS) database was analyzed to obtain group-specific procedure frequency as an estimate of procedure frequency in the general population.

Results: We reviewed 77 studies, and 52 met our inclusion criteria. Only 85% reported gender, and 21% reported ethnicity. Reporting of ethnicity was strongly associated with larger (>280 participants), multicenter, government-funded trials (P < .001 for all). Women are disproportionately under-represented in RCTs for all procedure categories (AAR, 9.0% vs 21.5%; CR, 30.0% vs 42.9%; LER, 22.4% vs 41.3%). Minorities are under-represented in AAR studies (6.0% vs 10.7%) and CR studies (6.9% vs 9.5%) but are over-represented in LER studies (26.0% vs 21.8%, P < .001 for all).

Conclusions: Minority ethnicity and female gender are under-reported and under-represented in vascular surgery RCTs, particularly in small, non-government-funded and single-center trials. The generalizability of some trial results may not be applicable to these populations. Greater effort to enroll a balanced study population in RCTs may yield more broadly applicable results.

Figure 1

Proportion of subjects enrolled in vascular surgery trials (RCT) compared with estimated proportion of patients receiving procedures (NIS) for female gender (A) and minority ethnicity (B). **P<.001 by chi-square.