Race, Ethnicity in Pulmonary Function Test Interpretation
Previous American Thoracic Society (ATS) standards for interpreting pulmonary function tests (PFTs) included race- and ethnicity-specific reference equations, however, a recent ATS statement challenged that practice and the idea that there is biological meaning behind race or ethnicity. Stephen Biehl, RRT, RPFT, who is the Supervisor of the Pulmonary Function Lab and Pulmonary Rehab at Temple University Hospital in Philadelphia, Pennsylvania answered questions about the impact that the ATS statement is making on clinical practice.
C360: Please explain the Global Lung Function Initiative (GLI) Network’s reference equations, including GLI-Other and GLI-Global
In 2017, the ATS recommended the use of GLI reference equations in North America.1 The GLI group that developed these equations was sponsored by the European Respiratory Society and included participation from ATS. The reference equations, released in 2012, cover people 3 to 95 years of age and used data from more than 74,000 people in 26 different countries, representing many more groups than other reference equations. GLI broke the data into four main ethnic groups; White (which included people who were Hispanic or from the United States, Europe, or North Africa) African American, North East Asian (North of Huaihe River/Qinling Mountains), and South East Asian (South of Huaihe River/Qinling Mountains). There is also a fifth group, Other, which is an average of the four groups to represent people from areas not included in the four main groups or of mixed heritage. The problem with GLI-Other is that the average of the data from the four groups is weighted more heavily toward the White group, as the majority of data is from this group. For this reason, a more balanced group, GLI-Global (released in 2022), was introduced, which assigns equality to each group when determining measurements within the normal range, but also gives wider margins of measurements within the normal range.2
C360: How are race-specific equations used to interpret pulmonary function tests?
Using race-specific equations to interpret pulmonary function tests (PFTs) allows certain groups of people to be compared with their peers based on their race or ethnicity. These equations are based on non-smoking individuals who identify with a certain racial or ethnic background based on their skin color. From this, the individual is compared with a healthy person of the same age, height, and biological sex. Using these predicted values based on race allows us to gauge how healthy an individual’s lungs may be.
The use of race as a means for categorizing individuals began by a physician named Samuel Cartwright, who was a proslavery Southern plantation owner. He determined that African Americans had a 20% lower predicted pulmonary function value compared with White individuals. The use of race-specific equations continued up to the most recent Global Lung Function Initiative Network’s (GLI) equations, where individuals can be categorized as White, Black, Northeast Asian, Southeast Asian, or Other. More recently, the GLI-Global was added.2
C360: What is the danger of using race-specific equations to interpret PFTs, according to the statement from the American Thoracic Society?
The use of race-specific equations can deter physicians from looking at other aspects that could potentially lead to lower values, including previous pulmonary infections, toxin inhalations (smoke, pollution, or climate), or nutrition, among other details that account for the societal or environmental factors. Excluding societal or environmental factors perpetuates structural racism by emphasizing the superficial appearance of a person’s skin color. This is thought to potentially cause a misdiagnosis, delay in the diagnosis, or prevent patients from getting the proper treatments.
The effort to define a person’s race or ethnicity has potential consequences when using race-correction factors. Most data used to create reference values are from limited areas and may not include large groups of individuals. For example, the Black reference values are based on African Americans, not Black people from Africa. Other populations from various racial and ethnic backgrounds are left out of a specified equation and lumped into the GLI-Other group.
C360: What evidence is there to eliminate the use of race in PFT reporting and interpretation?
Studies outlined in the journal CHEST have shown that socio-economic differences were more predictive than that of race for individuals.3 One study compared South Asian children living in an urban area of India with those living in an urban area of London. It also compared these children living in the urban area of India with those in rural India. While the forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were generally the same for the urban children in India and London, the children in rural India had significant differences. Differences were also seen between the urban South Asian children and White British children, but the FEV1/FVC ratio was similar in both.
Another study showed minimal differences between children in several different African countries with African American children. There was a significant difference, though, when compared with African children who were malnourished.
Both studies take us back to how John Hutchinson, the father of spirometry, categorized patients, which was according to their social class/ occupation.
C360: Please provide an overview of the new recommendations from ATS on race-neutral interpretations of PFTs.
The new ATS statement has several key conclusions and recommendations, including the need for PFT laboratories to become race-neutral. The statement recommends that laboratories use an average reference equation. ATS stated that since race and ethnicity were not biological characteristics, but based on appearance, this did not help to eliminate racism in medicine. The use of race-specific equations prevents proper diagnosis and treatment, could lead to medical harm, moves patients away from modifiable risks, and puts an emphasis on a person’s appearance. On the contrary, the use of race-neutral equations helps to provide better relationships between spirometry and symptoms, structure, functional capacity, and emphysema.
The second recommendation is for laboratories to switch to GLI-Global as the reference equation, as GLI-Global provides a weighted composite average for different ethnicities compared with using GLI-Other.
Thirdly, there needs to be an emphasis on treating the individual, aside from comparing them to a specific reference equation. Individuals change throughout their lives and have different genetic and socio-economic differences.
Fourthly, race-neutrality should not be applied to just spirometry but also needs to be applied to the diffusing capacity of the lungs for carbon monoxide and lung volumes. Another important recommendation is that further education on the importance of race neutrality in PFTs needs to be promoted and accepted. We must help to educate patients, other professionals, and other organizations on the importance of not basing results on the color of a person’s skin. Finally, more research needs to be done to quantify and clarify differences other than by race.
C360: When did Temple University Hospital implement the new guidelines and how did this implementation go?
Following the release of the official ATS statement on race and ethnicity in PFT interpretation in March of 2023,1 the leadership at Temple University Hospital met to implement these changes. The Medical Directors of Pulmonary and of Pulmonary Function Testing, as well as the Associate Vice President of Respiratory, Sleep, and Pulmonary Function were strong supporters of these changes. We evaluated the impact that it would have on our health system, the local and global communities that work with us, and on our research and education. We made every effort possible to alert physicians and other professionals of the changes. We remind those reviewing the results to look at the lung function changes over time and to treat the individual. Because of our support and dedicated work, we were able to implement the changes within a month of the official statement release.
C360: Is there anything else you would like to add?
Clinicians will see a difference in the results compared with the predicted values when comparing a race-neutral result to a race-specific result, and there should be a focus on treating the modifiable risk factors. Using a race-neutral equation, some clinicians may categorize patients as healthy or unhealthy, but they should not be deterred from providing patients with the most appropriate treatment. More research is needed to evaluate the changes, but continued efforts to weed out structural racism will lead to the best outcome for patients.
References:
1. Culver BH, Graham BL, Coates AL, et al. Recommendations for a standardized pulmonary function report. An official American Thoracic Society technical statement. Am J Respir Crit Care Med. 2017;196(11):1463-1472. doi:10.1164/rccm.201710-1981ST
2. Bhakta NR, Bime C, Kaminsky DA, et al. Race and ethnicity in pulmonary function test interpretation: an official American Thoracic Society statement. Am J Respir Crit Care Med. 2023;207(8):978-995. doi:10.1164/rccm.202302-0310ST
3. Marciniuk DD, Becker EA, Kaminsky DA, et al. Effect of race and ethnicity on pulmonary function testing interpretation: an American College of Chest Physicians (CHEST), American Association for Respiratory Care (AARC), American Thoracic Society (ATS), and Canadian Thoracic Society (CTS) evidence review and research statement. Chest. 2023;164(2):461-475. doi:10.1016/j.chest.2023.03.026