Experts Explore Barriers to Diversity in Respiratory Medicine Trials and Diagnostic Tools

In a scientific session at the American Thoracic Society (ATS) 2024 International Conference titled "An Inconvenient Truth: Health Disparities and Health Care Inequality in Respiratory Medicine," experts discussed the various areas within the field that are impacted by disparities.

The speakers agreed on a few key points: Addressing health care disparities in pulmonary arterial hypertension (PAH) and other respiratory diseases requires concerted efforts to improve data diversity, update diagnostic tools, and revise regulatory standards.

"You can see the racial disparities in the major PAH trials, the major PAH registries, and if we're not getting data from diverse populations, then we're not getting information that's relevant to those diverse populations," Gehan Davendra, MD, University of Hawaii. "Looking ahead to 'How can we at least address this one piece of the puzzle?', there's a lot of work out there on how to increase diversity in clinical trials."

Acknowledging how often mistrust appears as a barrier to diversity in clinical trials, she shared themes for tier 1 strategies that included ensuring personal health and safety and clear communication. Another strategy mentioned observing the practices of other medical fields to see how representation is being increased in those clinical trials.

"We know that there's a lot of race-based disparities in respiratory and pulmonary vascular medicine," Davendra said. "We need to focus on the root causes. Only in that way will we be able to develop strategies for more equitable health care. We obviously have a lot of work to do in terms of medical education and training and addressing this trust."

Ashraf Fawzy, MD, MPH, Johns Hopkins University, shed light on the ongoing issues surrounding the accuracy of pulse oximetry, particularly in relation to racial disparities. He elaborated on the fundamental principles of pulse oximetry, which utilizes 2 wavelengths of light—660 nm (red spectrum) and 940 nm (near-infrared spectrum)—to measure oxygen saturation. The accuracy of these measurements, however, is compromised by melanin in the skin, which also absorbs these wavelengths, leading to potential inaccuracies.

Fawzy supported this by sharing historical context through a 1990 study by Martin Tobin, which highlighted that pulse oximeters tend to be less precise for Black patients compared with White patients.¹ Despite this early recognition, the issue remained largely unaddressed until the COVID-19 pandemic, which renewed focus on the problem. A significant study from the University of Michigan in 2020 also demonstrated that occult hypoxemia (true oxygen saturation below 88% despite pulse oximeter readings of 92%-96%) was more common in Black patients compared with White patients, a finding that was replicated in subsequent research.²

The presentation then detailed a study conducted by Fawzy et al., which confirmed these disparities and further explored the clinical implications. Using data from patients who had COVID-19, the researchers found that pulse oximeter inaccuracies disproportionately affected Black and Hispanic patients, leading to delayed recognition and treatment. Specifically, more than half of the patients who had their need for treatment unrecognized were Black, and a significant portion were Hispanic. These inaccuracies persisted even after adjusting for potential confounders.³

The inconsistency of pulse oximetry readings over time was another critical point highlighted by Fawzy, who cited various research showing that pulse oximeter accuracy varied throughout hospital encounters, often providing both overestimations and underestimations within the same patient’s stay.

He discussed the regulatory shortcomings that contribute to this issue. The FDA currently requires pulse oximeter manufacturers to test devices on a minimal number of subjects with dark skin pigmentation in controlled settings that do not reflect real-world clinical environments, he explained. This insufficient testing protocol leads to devices that perform inequitably across different skin tones.

In terms of solutions, Fawzy dismissed the idea of applying a correction factor for race as inappropriate. Instead, he suggested that higher oxygen saturation targets might be necessary for certain patients, although this approach carries the risk of hyperoxia. Importantly, there is a need for technological advancements in pulse oximetry, as the current devices are based on technology that has seen little innovation in over 50 years. Regulatory updates and extensive research, both prospective and retrospective, are essential to develop more accurate and equitable pulse oximetry practices.

Fawzy concluded by calling for continued attention and research into this critical issue, emphasizing the need for equitable health care practices that accurately reflect the diverse patient populations they serve.

Overcoming mistrust, ensuring clear communication, and addressing logistical barriers are crucial steps toward more equitable health care that were emphasized by the speakers. Integrating lessons from other medical fields and adopting race-neutral diagnostic approaches also can help mitigate the impact of systemic biases and improve health outcomes for minority populations.

References

1. Jubran A, Tobin MJ. Reliability of pulse oximetry in titrating supplemental oxygen therapy in ventilator-dependent patients. Chest. 1990;97(6):1420-1425. doi:10.1378/chest.97.6.1420

2. Sjoding MW, Dickson RP, Iwashyna TJ, Gay SE, Valley TS. Racial bias in pulse oximetry measurement. N Engl J Med. 2020;383(25):2477-2478. doi 10.1056/NEJMc2029240

3. Fawzy A, Wu TD, Wang K, et al. Racial and Ethnic Discrepancy in Pulse Oximetry and Delayed Identification of Treatment Eligibility Among Patients With COVID-19. JAMA Intern Med. 2022;182(7):730–738. doi:10.1001/jamainternmed.2022.1906