The Current State of Diversity in Randomized Clinical Trials for Peripheral Artery Disease


With significant race and sex disparities in the area of peripheral artery disease, a study shows that clinical trials often lack representative patient populations.

Image Credit: © Jakub Krechowicz -

Image Credit: © Jakub Krechowicz -

A recent study published by the National Library of Medicine reviewed diversity in randomized clinical trials (RCTs) for peripheral artery disease (PAD).1 Disparities in race and sex are well-known challenges in the prevalence, diagnosis, and outcomes of PAD.

“In addition to substantial morbidity, PAD imposes a significant financial burden on patients and society,” the study authors wrote. “In the US, the direct medical costs of PAD amount to $6.3 billion. Disparities in PAD diagnosis and treatment extend to differences in costs and utilization: among hospitalized patients with PAD, costs and length of stay differ significantly based on a patient’s race/ethnicity. Endovascular interventions for PAD have shown promise in clinical trials, but these trials often lack diverse patient groups that accurately represent the affected population. Disparities in PAD care and the need to enhance diversity in clinical trials have been noted in previous studies, and multiple calls to address this lack of diversity exist.”

PAD is a common condition in which narrowed arteries reduce blood flow to the arms or legs. It is usually a strong indicator of the buildup of fatty deposits in the arteries, which can lead to other serious complications.2

According to an American Heart Association Scientific Statement published in Circulation, PAD is present in over 12 million Americans and 200 million people worldwide. Black, Hispanic, and Native Americans with PAD are less likely to undergo revascularization procedures and have 10%-30% higher rates of complications as compared to White patients with PAD.3

The authors of the study identified 2,374 records of RCTs for PAD, with 59 meeting the inclusion criteria. This group consisted of 35 trials, 14 publications, and 10 protocols. “Descriptive analysis was used to summarize trial characteristics, publication or study protocol characteristics, and the reporting of demographic characteristics. Meta-regression was used to explore associations between demographic characteristics and certain trial characteristics,” the authors wrote.

The results of the analysis confirmed demographic information in the publications was frequently missing. Only four reported information on race/ethnicity, while none of them reported on socioeconomic or marital status. Additionally, disparities in sex were revealed with women accounting for only 33% of participants across the 14 publications. The authors did find that the number of women enrolled in the trials increased from 2012 to 2019, according to the meta-regression analysis; however, they deemed this finding to be non-significant.

Findings from the analysis confirmed the belief that there is a lack of awareness in clinical trials for PAD. This often comes from biases in site location and selecting participants from clinical and academic settings, among others. The authors suggest an increase in investments to diversify resources, focusing on bringing the trials to regions and populations that are often underrepresented.

“The findings of this review highlight potential issues that may compromise the reliability and external validity of study findings in lower-extremity PAD RCTs when applied to the real-world population. Addressing these issues is crucial to enhance the generalizability and impact of clinical trial results in the field of PAD, ultimately leading to improved clinical outcomes for patients in underrepresented populations,” the authors concluded.


  1. Long C, Williams AO, McGovern AM, Jacobsen CM, Hargens LM, Duval S, Jaff MR. Diversity in randomized clinical trials for peripheral artery disease: a systematic review. Int J Equity Health. 2024 Feb 13;23(1):29. doi: 10.1186/s12939-024-02104-8. PMID: 38350973; PMCID: PMC10865563.
  2. Peripheral artery disease (PAD). Mayo Clinic. June 21, 2022. Accessed February 29, 2024.
  3. Health Disparities in Peripheral Artery Disease: A Scientific Statement From the American Heart Association. Circulation 2023;148:286-296.
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