Race-Specific Lung-Function Values May Skew IPF Testing

HONOLULU – Old habits die hard, especially when it comes to pulmonary function testing in a diverse population of patients with interstitial lung disease (ILD).

Specifically, pulmonary care clinicians may be habitually relying on outdated and inaccurate race-specific reference values when evaluating respiratory impairment in persons of African and Hispanic/Latino ancestry, which can result in underrecognition, underdiagnosis, and undertreatment, reported Ayodeji Adegunsoye, MD, from the University of Chicago, and colleagues.

"Our results make a compelling case for re-evaluating the use of race as a physiological variable, and highlight the need to offer equitable and optimal care for all patients, regardless of their race or ethnicity," Dr. Adegunsoye said in an oral abstract session at the annual meeting of the American College of Chest Physicians (CHEST).

Flawed assumptions

In an interview, Dr. Adegunsoye noted that race-specific notions, such as the automatic assumption that Black people have less lung capacity than White people, are baked into clinical practice and passed on as clinical wisdom from one generation of clinicians to the next.

Pulmonary function reference values that are used to make a diagnosis of idiopathic pulmonary fibrosis in Black or Hispanic/Latino patients "appear flawed when we use race-specific values. And beyond the diagnosis, it also appears to impact eligibility for key interventional strategies for managing the disease itself," he said.

The use of race-specific equations can falsely inflate percent-predicted pulmonary function values in non-White patients, and make it seem as if a patient has normal lung function when in fact he may have impaired function.

For example, using race-based reference values a Black patient and a White patient may appear to have the same absolute forced vital capacity readings, but different FVC percent predicted (FVCpp), which can mean a missed diagnosis.

Investigators who studied the association between self-identified race and visually identified emphysema among 2,674 participants in the Coronary Artery Risk Development in Young Adults study found that using standard equations to adjust for racial differences in lung-function measures appeared to miss emphysema in a significant proportion of Black patients.

PF registry study

In the current study, to see whether the use of race-neutral equations for evaluating FVCpp could change access to health care in patients with ILD, Dr. Adegunsoye and colleagues used both race-specific and race-neutral equations to calculate FVCpp values among separate cohorts of Black, Hispanic/Latino, and White patients enrolled in the Pulmonary Fibrosis Foundation Patient Registry who had pulmonary functions test within about 90 days of enrollment.

The race-specific equations used to calculate FVCpp was that published in 1999 by Hankinson and colleagues in American Journal of Respiratory and Critical Care Medicine. The race-neutral Global Lung Function Initiative (GLI) equations by Bowerman and colleagues were developed in 2022 and published in March 2023 in the same journal.

The investigators defined access to care as enrollment in ILD clinical trials for patients with FVCpp greater than 45% but less than 90%, and US payer access to antifibrotic therapy for patients with FVCpp of greater than 55% but less than 82%.

They found that 22% of Black patients were misclassified in their eligibility for clinical trials in each of two scenarios – those who would be excluded from trials using the 1999 criteria but included using the 2022 criteria, and vice versa, that is included with 1999 criteria but excluded by the 2022 GLI criteria. In contrast, 14% of Hispanic Latino patients and 12% of White patients were misclassified.

Using the 1999 criteria to exclude patients because their values were ostensibly higher than the upper cutoff meant that 10.3% of Black patients who might benefit would be ineligible for clinical trial, compared with 0% of Hispanic/Latinos and 0.1% of Whites.

Similarly, 11.5% of Black patients but no Hispanic/Latino or White patients would be considered eligible for clinical trials using the old criteria but ineligible under the new criteria.

Regarding antifibrotic therapy eligibility, the respective misclassification rates were 21%, 17%, and 19%.

"Our study showed that use of race-specific equations may confound lung function tests, potentially leading to misclassification, delayed diagnosis, and inadequate treatment provision. While our study suggests potential disparities in access to health care for patients with interstitial lung disease facilitated by race-specific equations, further research is required to fully comprehend the implications," the investigators wrote.

ATS statement

In an interview, Juan Wisnievsky, MD, DrPh, from Mount Sinai Medical Center, New York, who also chairs the Health Equity and Diversity Committee for the American Thoracic Society, pointed to a recent ATS statement he coauthored citing evidence for replacing race and ethnicity-specific equations with race-neutral average reference equations.

"This use of race and ethnicity may contribute to health disparities by norming differences in pulmonary function. In the United States and globally, race serves as a social construct that is based on appearance and reflects social values, structures, and practices. Classification of people into racial and ethnic groups differs geographically and temporally. These considerations challenge the notion that racial and ethnic categories have biological meaning and question the use of race in PFT interpretation," the statement authors wrote.

"There is some agreement that race-based equations shouldn’t be used, but all the potential consequences of doing that and which equations would be the best ones to use to replace them is a bit unclear," Dr. Wisnievsky said.

He was not involved in the study by Dr. Adegunsoye and colleagues.

Data used in the study were derived from research sponsored by F. Hoffman–La Roche and Genentech. Dr. Adegunsoye disclosed consultancy fees from AbbVie, Inogen, F. Hoffman–La Roche, Medscape, and PatientMpower; speaking/advisory fees from Boehringer Ingelheim; and grants/award from the CHEST Foundation, Pulmonary Fibrosis Foundation, and National Institutes of Health. Dr. Wisnievsky had no relevant disclosures.

This story originally appeared on MDedge.com, part of the Medscape Professional Network.

Comments

Commenting is limited to medical professionals. To comment please Log-in.

Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.