How Race-Neutral Equations for Pulmonary Testing Affect Patients

The use of newly developed race-neutral reference equations for pulmonary function test (PFT) interpretation led to a significant increase in both the prevalence and severity of respiratory impairments among Black patients compared with current race-specific reference equations, a cross-sectional study showed.

Among Black patients, use of the race-neutral equations was associated with increases in the prevalence of restriction from 26.8% to 37.5%, as well as the prevalence of a nonspecific pattern of impairment from 3.2% to 6.5%, reported Alexander T. Moffett, MD, of the University of Pennsylvania in Philadelphia, and co-authors.

On the other hand, use of these new equations among white patients was associated with a decrease in the prevalence of restriction from 22.6% to 18% and nonspecific pattern of impairment from 8.7% to 4%, they noted in JAMA Network Open.

The race-neutral reference equations were also associated with an increase in severity in 22.8% of Black patients and a decrease in severity in 19.3% of white patients compared with the race-specific reference equations.

For both Black and white patients, there were no significant changes in the percentage with obstruction.

Moffett and colleagues noted that the use of race in clinical prediction models has resulted in substantial debate.

“As race is a sociocultural construct without biological basis, observed racial differences in health reflect systemic racism and discrimination rather than innate genetic differences between racial or ethnic groups,” they wrote. “The inclusion of race in prediction models may therefore function to mask the consequences of systemic racism, perpetuate biological essentialism, and ultimately widen health disparities.”

They pointed out that biological differences as the result of race alone have been repeatedly disproven.

In an invited commentary, Adam Gaffney, MD, MPH, of Harvard Medical School in Boston, further described just how harmful and dangerous the consequences of race-specific guidelines can be, including potentially delaying essential care such as rehabilitation or even transplantation for Black patients.

“Such consequences should be of great concern to the pulmonary community. After all, multiple studies have found that the racial gap in lung function is not benign and is instead associated with harm, such as higher all-cause mortality in the general population or worse disease-specific outcomes among those with COPD [chronic obstructive pulmonary disease],” he wrote. “Treating Black and white patients with lung disease with identical absolute lung function differently is tantamount to discriminatory care.”

In another invited commentary, Lundy Braun, PhD, and Ricky Grisson, MD, MPH, MBA, of Brown University in Providence, Rhode Island, noted that implementing race-neutral equations may improve how we look at lung health as a whole.

“We are now at a seminal moment in pulmonology when many activists and researchers are questioning the practice of race correction,” the pair wrote.

“And yet, questions remain about this race-neutral prediction equation, which is based on a statistical technique of weighting biologically informed racial categories,” Braun and Grisson continued. “We need to build on this important work to find better ways both to measure more accurately the impact of racism on pulmonary function and to explore more rigorously the biological processes by which racism damages the lungs of people of other racial and ethnic groups globally.”

The race-neutral equations were developed by the Global Lung Function Initiative in 2022, building on equations that were produced using race and ethnicity from a decade prior.

Previous reference equations used different thresholds for determining “abnormal” PFT results, with Black patients requiring lower scores than their white counterparts. Recently, the American Thoracic Society issued a statement encouraging the use of race-neutral reference equations for PFT interpretation, with the aim of eliminating these factors.

For this study, Moffett and team used the race-neutral reference equations to interpret PFTs conducted at an academic medical center from January 2010 to December 2020. A total of 2,722 Black and 5,709 white patients were included in the study. Among Black patients, mean age was 51.8 and 25.4% were men, while for white patients, mean age was 56.4 and 46.5% were men.

Study limitations included applicability to other populations, as only white and Black patients were analyzed in this study. The researchers also noted that the Global Lung Function Initiative reference equations are race-neutral, not race-blind, and still may have unintended effects in clinical practice.