Getting patients in the door is only part of the problem when it comes to improving the diagnosis of lung disease. For Black patients, a more insidious concern lies in the system used to make diagnoses.

When a patient reports respiratory symptoms, such as chronic cough or shortness of breath, lung function testing is often performed. Their test results are then compared to those of healthy individuals of a similar demographic to help determine whether the patient’s breathing is abnormal. Until recently, the American Thoracic Society recommended that a patient’s results be measured against others of similar age, height, sex, and race using equations developed by the Global Lung Function Initiative in 2012. While the former are biologically meaningful, race is a sociocultural construct without biological basis. The use of race in pulmonary function test interpretation thus controls not for biological difference, but instead for the effects of structural racism, say LDI Fellows Alexander Moffett, Gary Weissman, Scott Halpern, and colleagues.

To explore just how big of an impact race-specific equations have on Black and white patients, their team used newly developed race-neutral reference equations and compared their output to those of race-specific equations. The race-neutral equations use the same data and statistical methodology as the original equations, except they do not encode race as a predictor of lung function.

They found that a switch from race-specific to race-neutral equations led to an 11 percentage point increase in the number of Black patients with a restrictive respiratory impairment. Conversely, the number of white patients who were identified as having a restriction decreased by almost five percentage points.

The researchers also found that the switch to race-neutral reference equations led to almost one-fourth of Black patients being newly flagged as having greater disease severity. While this led to changes in identification in only a few hundred patients in this study, the researchers estimate that by using race-neutral equations on a national scale, up to 1 million new cases of impairment could be identified in Black patients.

It remains to be seen what the impact lower rate of identification due to race-specific equations is having on patient outcomes. In clinical practice, these equations are used as only one piece of information among other considerations. Yet, the interpretation of the results of these equations informs clinician decisions on tests, diagnoses, and treatments.

Disparities in these areas have far-reaching implications in terms of the allocation of medical resources: If a Black patient is less likely to be identified as having more severe disease, this makes them less likely to be offered certain treatments or sent for additional testing, for example. Even so, switching to race-neutral equations is just one step among many required to make the system more equitable. It’s also important to address the social, political, and economic pitfalls that have led to Black patients having lower levels of average lung function on a nationwide level in the first place.

The study, “Global, Race-Neutral Reference Equations and Pulmonary Function Test Interpretation”, was published on June 1, 2023 in JAMA Network Open. Authors include Alexander Moffett, Cole Bowerman, Sanja Stanojevic, Nwamaka Eneanya, Scott Halpern, and Gary Weissman.


Madison Weiss

Dominic Weiss

Policy Coordinator

More on Health Equity