Emphysema missed among Black men in US due to race-adjusted lung tests

Poorly supported assumptions about typical levels of lung function among Black men in the US are leading medics to miss cases of emphysema

By Carissa Wong

Black men in the US who are in their fifties may be more than six times more likely than white men of the same age to have emphysema when lung function tests deem them to have better-than-normal lung function. The findings highlight the need to remove calculations that account for race in medical tests in order to tackle health inequalities.

“It was surprising to see these considerable rates of emphysema in Black men who we would consider to have above normal lung function,” said Gabrielle Liu at Northwestern University in Chicago. “It does make a big difference whether or not somebody is actually diagnosed with having [poor] lung function versus being told they have normal or above normal lung function, because it impacts what the clinician recommends.”

Emphysema is an irreversible condition in which tiny air sacs – called alveoli – in the lungs are damaged by toxic chemicals from smoking and air pollution, causing shortness of breath. Diagnosis involves tests that assess a person’s ability to inhale and exhale, and current treatments provide symptom-relief through drugs that expand the airways.

However, the standard lung function tests used by doctors to assess someone’s lung health are calibrated according to a person’s race based on unfounded ideas that there are inherent biological differences between people from differing ethnic groups.

Liu and her colleagues analysed medical data from a total of 2674 Black and white people in the US in their fifties who had taken part in a separate study into cardiovascular disease. By looking at pictures of the participants’ lungs, which were taken in 2010, and the results of race-adjusted breathing tests the participants took in 2015, the team established how well the lung function tests flagged up emphysema in all participants.

They found that 12.2 per cent of Black men who were classed as having above normal lung function in 2015 actually had emphysema, which showed up clearly in the lung images taken in 2010. In contrast, just 2 per cent of white men who were classed as having above normal lung function in 2015 actually had emphysema.

“Since emphysema is irreversible, our study probably underestimates the number of emphysema cases that would be missed according to lung function tests, given the five year gap between visible signs of emphysema in the lung images and the lung function tests,” says Liu.

The team then removed the race-based adjustments applied to the lung test data collected in 2015. Doing so removed the problem: no Black men with emphysema were incorrectly classed as having above normal lung function. The researchers presented their work at the ATS 2022 conference.

“I think the evidence shows we really need to stop using race-adjustments in lung tests. Over the past few years the evidence is growing – they are contributing to racial disparities in healthcare,” says Liu.