Pulse oximeters’ inaccuracies in darker-skinned people require urgent action, AGs tell FDA

More than two dozen attorneys general are urging Food and Drug Administration officials to take urgent action to address disparities in how well pulse oximeters, the fingertip devices used to monitor a person’s oxygen levels, work on people with darker skin.

In a Nov. 1 letter, the AGs noted that it had been a year since the FDA convened a public meeting of experts, who called for clearer labeling and more rigorous testing of the devices, and that no action had been taken.

“We, the undersigned Attorneys General, write to encourage the FDA to act with urgency to address the inaccuracy of pulse oximetry when used on people with darker toned skin,” said the letter, written by California Attorney General Rob Bonta and signed by 24 other attorneys general.

Pulse oximeters’ overestimation of oxygen levels in patients with darker skin has, in a slew of recent research studies, been linked to poorer outcomes for many patients because of delayed diagnosis, delayed hospital admissions, and delayed access to treatment, including for severe Covid-19 infections. Higher amounts of pigments called melanin in darker skin interfere with the ability of light-based sensors in pulse oximeters to detect oxygen levels in blood.

“It is imperative that the FDA act now to prevent additional severe illness and mortalities among darker skinned people resulting from inaccurate or misleading pulse oximeter readings,” said the letter, which cited STAT’s extensive reporting on the issue.

The letter expressed concern about “the risk of pulse oximeters’ incorporation into other diagnostic tools or medical technologies” that are being developed and said “software or other tools that make predictions of future health care needs based on past pulse oximetry data with embedded color bias could end up reproducing health disparities based on race.”

The letter also said it was “especially troubling” that pulse oximeters could be contributing to the nation’s “current, avoidable crisis” of maternal and infant mortality, which is much worse in Black populations. “It is unconscionable in a multi-racial, multi-ethnic nation …[that] the pulse oximeter is not calibrated to adjust for skin color,” the letter stated.

The delay has frustrated health care workers who use pulse oximeters and have studied them and followed the progress toward creating new devices that work better. “I just get mad that these things are not on the market,” Theodore J. Iwashyna, an ICU physician at Johns Hopkins, told STAT. “Just last week in my ICU, I had a patient whose pulse oximeter was reading 100% at the same time that his arterial blood gas showed that his oxygen levels were dangerously low. I need these things to work, and work in all my patients.”

The last information posted by the agency on its page about pulse oximeter limitations was on Nov. 7, 2022, six days after the expert panel met, and stated: “The FDA is reviewing the committee’s recommendations and will consider additional actions as needed. The FDA will share with the public any additional updates to the information and recommendations below.” The agency’s website lists a draft guidance about pulse oximeters among the guidances the Center for Devices and Radiological Health plans to publish in 2024.

After this article was published, an FDA spokesperson told STAT that it is “a high priority for the agency to ensure that oximetry device performance is equitable and accurate for all U.S. patients” and that the agency would be responding directly to the offices of the attorneys general. The spokesperson added that the issues involving pulse oximeters are complex and the agency is working to improve premarket evaluation strategies and equitable device performance. It plans to publish a discussion paper to gather additional feedback and convene another meeting with independent experts, the spokesperson said, but gave no timeline.

The attorneys general’s letter asked for specific actions from the FDA, including requiring manufacturers to provide warnings about the reduced effectiveness of their devices; a better statement of warning about the devices on the FDA website; issuance of a letter to health care providers about the risks of the devices for patients with darker skin; an accelerated timeline for review of the recommendations; and updated regulations that require testing of devices on more diverse populations.

“This could be a breakthrough,” said Iwashyna. “Give our hospitals the ability to review rigorous data on how new devices function in different patient groups.”

Some physicians said the requests should go further, and include a focus on those who purchase the devices. “Doctors and nurses should know about the problems with pulse oximeters, but they do not make the decision to buy these devices in their institutions,” said Kadija Ferryman, a bioethicist and assistant professor at Johns Hopkins. “This kind of letter might be better addressed to health care administrators and others in health care institutions with device-purchasing power, to make sure they understand the ways in which their decisions put patients at risk.”

Nearly all of those signing the letter are Democrats, but the list includes two Republicans: Dave Yost of Ohio, and Sean Reyes of Utah. Bonta, the California attorney general who led the coalition that signed the letter, has been working on a number of issues involving racial and ethnic bias in health care, including launching an inquiry into whether algorithms used by health care facilities to make health care decisions may lead to disparities.

“Ultimately, patients of color need and deserve technology that works as well for them as it does for the predominantly white patient population with whom this tool was originally designed and tested,” said the letter.

This story has been updated with a response from the FDA.