Pulse Oximetry Potential Source of Racial Disparity in COVID-19 Care

Researchers show that pulse oximetry, which is a gatekeeper in treatment decisions for COVID-19 patients, overestimates blood oxygen levels in people of color.

In a new study involving more than 7,000 COVID-19 patients, pulse oximeter devices overestimated blood oxygen levels in Asian, Black, and non-Black Hispanic patients, which could have affected their eligibility for treatment.

Pulse oximetry, which measures blood oxygen saturation levels based on blood pulse and the relative absorbance of two wavelengths of light, is used for triage and treatment decisions in the care of COVID-19 patients. Low blood oxygen saturation levels prompt interventions for COVID-19 patients.

Earlier research has shown that pulse oximetry overestimates blood oxygen saturation in people with skin of darker pigmentation compared to people with lighter pigmentation.

COVID-19 has had a disproportionate impact on people of color, including Black, Hispanic, American Indian, Alaskan Native, and Native Hawaiian and other Pacific Islander people, according to the Centers for Disease Control and Prevention.

The new study, which was published by JAMA Internal Medicine, examined data from five referral centers and community hospitals in the Johns Hopkins Health System.

The analysis included reviewing data from more than 1,200 COVID-19 patients who had their blood oxygen saturation levels measure by both pulse oximetry and arterial blood gas testing. That review showed pulse oximetry overestimated arterial oxygen saturation among Asian, Black, and non-Black Hispanic patients compared with White patients.

The analysis also included reviewing data from more than 6,500 other COVID-19 patients with pulse oximetry measurements, with predicted overestimation of arterial oxygen saturation levels for 1,900 patients associated with failure to identify many Black and non-Black Hispanic patients who were eligible to receive COVID-19 treatment.

The study includes two key data points.

• When compared to White COVID-19 patients, pulse oximetry overestimated blood oxygen levels by 1.7% for Asian patients, 1.2% for Black patients, and 1.1% for non-Black Hispanic patients.
   
• Compared to White COVID-19 patients, Black patients were 29% less likely to have their treatment eligibility recognized by pulse oximetry and non-Black Hispanic patients were 23% less likely to have their treatment eligibility recognized by pulse oximetry.

Bias in pulse oximetry could contribute to health disparity in care for COVID-19 and other respiratory conditions, the study's co-authors wrote. "We found statistically significant and persistent overestimation of arterial oxygen saturation by pulse oximetry among Asian, Black, and Hispanic patients compared with non-Hispanic White patients. Black and Hispanic patients were more likely to experience unrecognized and delayed recognition of eligibility to receive COVID-19 therapy. Differential inaccuracies in pulse oximetry should be examined as a potential explanation for disparities in COVID-19 outcomes and may have implications for the monitoring and treatment of other respiratory illnesses."

Pulse oximetry inaccuracy can impact treatment for COVID-19, particularly for people of color, study co-author Tianshi David Wu, MD, MHS, an assistant professor of medicine at Baylor College of Medicine, said in a prepared statement. "Because eligibility for many COVID-19 medications depends on oxygen levels, pulse oximeter tools have become de facto gatekeepers for how we treat patients with this condition. We've shown that biases in pulse oximeter accuracy can mean the difference between receiving a necessary medication and not—and, critically, we were able to quantify how much this disproportionately affects minority communities."

Related: Study Finds Racial and Ethnic In-Hospital Mortality Disparities During Pandemic