Addressing Race in Pulmonary Function Testing by Aligning Intent and Evidence With Practice and Perception

Abstract

The practice of using race or ethnicity in medicine to explain differences between individuals is being called into question because it may contribute to biased medical care and research that perpetuates health disparities and structural racism. A commonly cited example is the use of race or ethnicity in the interpretation of pulmonary function test (PFT) results, yet the perspectives of practicing pulmonologists and physiologists are missing from this discussion. This discussion has global relevance for increasingly multicultural communities in which the range of values that represent normal lung function is uncertain. We review the underlying sources of differences in lung function, including those that may be captured by race or ethnicity, and demonstrate how the current practice of PFT measurement and interpretation is imperfect in its ability to describe accurately the relationship between function and health outcomes. We summarize the arguments against using race-specific equations as well as address concerns about removing race from the interpretation of PFT results. Further, we outline knowledge gaps and critical questions that need to be answered to change the current approach of including race or ethnicity in PFT results interpretation thoughtfully. Finally, we propose changes in interpretation strategies and future research to reduce health disparities. The practice of using race or ethnicity in medicine to explain differences between individuals is being called into question because it may contribute to biased medical care and research that perpetuates health disparities and structural racism. A commonly cited example is the use of race or ethnicity in the interpretation of pulmonary function test (PFT) results, yet the perspectives of practicing pulmonologists and physiologists are missing from this discussion. This discussion has global relevance for increasingly multicultural communities in which the range of values that represent normal lung function is uncertain. We review the underlying sources of differences in lung function, including those that may be captured by race or ethnicity, and demonstrate how the current practice of PFT measurement and interpretation is imperfect in its ability to describe accurately the relationship between function and health outcomes. We summarize the arguments against using race-specific equations as well as address concerns about removing race from the interpretation of PFT results. Further, we outline knowledge gaps and critical questions that need to be answered to change the current approach of including race or ethnicity in PFT results interpretation thoughtfully. Finally, we propose changes in interpretation strategies and future research to reduce health disparities. Soon after John Hutchinson developed a spirometer (c. 1840) that was easier to deploy than its predecessors, he and others recorded the vital capacity of the lungs from a large number of people. The data showed that vital capacity increased with height, declined with age in adulthood, differed between sexes, and varied by occupation (eg, typesetter vs firefighter).1Hutchinson J. On the capacity of the lungs, and on the respiratory functions, with a view of establishing a precise and easy method of detecting disease by the spirometer.Med Chir Trans. 1846; 29: 137-252Crossref PubMed Google Scholar Another early and consistent observation was that vital capacity varied between social classes.1Hutchinson J. On the capacity of the lungs, and on the respiratory functions, with a view of establishing a precise and easy method of detecting disease by the spirometer.Med Chir Trans. 1846; 29: 137-252Crossref PubMed Google Scholar Subsequently, descriptions ascribed to social class were overtaken by studies focused on capturing population differences by the sociopolitical construct of race.2Yang T.S. Peat J. Keena V. Donnelly P. Unger W. Woolcock A. A review of the racial differences in the lung function of normal Caucasian, Chinese and Indian subjects.Eur Respir J. 1991; 4: 872-880PubMed Google Scholar Average vital capacity for the same sex, height, and age was reported to be lower in non-White compared with White groups. Although some investigators argued for environmental sources for these differences—for example, early-life nutrition, respiratory illnesses, air pollution, exercise, and altitude—the mechanisms and quantification of these effects were not pursued systematically; rather, a narrative of innate differences took hold.3Myers J.E. Differential ethnic standards for lung functions, or one standard for all?.S Afr Med J. 1984; 65: 768-772PubMed Google Scholar The observed population differences in vital capacity were coopted and often used to justify and uphold slavery and structural racism in the United States.4Braun L. Race correction and spirometry: why history matters.Chest. 2020; 159: 1670-1675Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar Discriminatory practices were not limited to skin color, as a proclamation of these observed “innate” differences in lung function were used to deny the disability claims of Welsh vs English White miners.5McGuire C. ‘X-rays don’t tell lies’: the Medical Research Council and the measurement of respiratory disability, 1936-1945.Br J Hist Sci. 2019; 52: 447-465Crossref PubMed Scopus (3) Google Scholar In this social milieu where race and structural racism reinforced each other, and where race was thought to capture innate differences, clinicians and researchers incorporated race into their interpretation algorithms with the intent of improved prediction of expected lung function. Herein, we explore the consequences of embedding race in the interpretation of spirometry, highlight important considerations that influence interpretation strategies, and discuss challenges and alternatives to current practice. Decades of epidemiologic studies have found that the extent to which lung function measured by spirometry is reduced compared with what is expected is associated with respiratory disease and death; notably, these associations also were observed for nonrespiratory disease and for overall mortality.6Schunemann H.J. Dorn J. Grant B.J. Winkelstein Jr., W. Trevisan M. Pulmonary function is a long-term predictor of mortality in the general population: 29-year follow-up of the Buffalo Health Study.Chest. 2000; 118: 656-664Abstract Full Text Full Text PDF PubMed Scopus (474) Google Scholar, 7Kannel W.B. Hubert H. Lew E.A. Vital capacity as a predictor of cardiovascular disease: the Framingham study.Am Heart J. 1983; 105: 311-315Crossref PubMed Scopus (145) Google Scholar, 8Duong M. Islam S. Rangarajan S. et al.Mortality and cardiovascular and respiratory morbidity in individuals with impaired FEV1 (PURE): an international, community-based cohort study.Lancet Glob Health. 2019; 7: e613-e623Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar Pulmonary function tests (PFTs) show improvements in lung growth and attenuation in decline after reduction of harmful exposures such a smoking and air pollution.9Gauderman W.J. Urman R. Avol E. et al.Association of improved air quality with lung development in children.N Engl J Med. 2015; 372: 905-913Crossref PubMed Scopus (401) Google Scholar, 10Downs S.H. Schindler C. Liu L.J. et al.Reduced exposure to PM10 and attenuated age-related decline in lung function.N Engl J Med. 2007; 357: 2338-2347Crossref PubMed Scopus (288) Google Scholar, 11Anthonisen N.R. Connett J.E. Murray R.P. Smoking and lung function of Lung Health Study participants after 11 years.Am J Respir Crit Care Med. 2002; 166: 675-679Crossref PubMed Scopus (558) Google Scholar Spirometry results are reported as both an absolute number in the appropriate units—liters of air for vital capacity—and as a relative number compared with an expected value for a healthy, nonsmoking population of similar age, height, and sex. Consistent with widespread historical and current practice, guidelines recommend that expected values are calculated from equations derived in a representative population (ie, similar racial or ethnic identity) of otherwise healthy individuals.12Pellegrino R. Viegi G. Brusasco V. et al.Interpretative strategies for lung function tests.Eur Respir J. 2005; 26: 948-968Crossref PubMed Scopus (3931) Google Scholar Although this approach is distinct from the historic—and no longer recommended—practice of applying a correction factor for non-White populations to expected values derived from White populations, it still represents a form of so-called norming that requires critical re-evaluation. This approach relies on patient self-identity or the technologist’s impression of someone’s racial or ethnic background based on skin color or surname. Hundreds of reference equations have been published for different populations around the world. Current guidelines recommend using the spirometry equations from the Global Lung Function Initiative derived from large nonsmoking populations without respiratory conditions collected across multiple S. et reference values for spirometry for the age the global lung function Respir J. PubMed Scopus Google Scholar how observed differences in lung function across racial and ethnic the range of the observed a on the lower observed lung function non-White reference equations values that are lower for non-White groups. for with the same absolute of lung function, the non-White have a relative value compared with the White The of FEV1 to which is to the of lung not on in and is similar across race or ethnicity in both and S. et reference values for spirometry for the age the global lung function Respir J. PubMed Scopus Google Scholar PFT such as capacity and lung also are found to be lower in non-White with spirometry, we not use or This is in because of in that to equations in non-White populations have been J. The of pulmonary capacity in a of J Respir Crit Care Med. PubMed Scopus Google Scholar, G. in healthy an with a PubMed Scopus Google Scholar, G. capacity prediction in without lung PubMed Scopus Google Scholar The effects of reference equations are an lung function is measured the of disease and data are This for individuals are for a decline in or relative lung growth in such as for exposure to with of pulmonary in or after lung In these large changes or a decline in an measured absolute lung function that what is expected from a a from the expected with is than a relative in the general of how are a lung function disease is Vital capacity and of lung function are in by the of the with the same may not have the same the in observed values in healthy A question is lung function be compared with healthy reference data by to height, as is the current practice, or of such as This is because multiple studies have differences in the of to between racial and ethnic The of and on the racial in lung J Respir Crit Care Med. PubMed Scopus Google R. and in and their in to pulmonary function Afr Med J. Google Scholar The for the observed differences may and in height, also with that influence height, including early-life and and such as respiratory and exposures to and pollution, and R. E. H. of and exposure on and pulmonary function in and J PubMed Scopus Google Scholar, and of and from to in and a of studies with 2020; Full Text Full Text PDF PubMed Scopus Google Scholar, J. et and of air on respiratory a for Respir J. PubMed Scopus Google Scholar, et of by of and important for J 2015; Full Text Full Text PDF PubMed Scopus Google Scholar The use of of lung differences between and White populations by to The of and on the racial in lung J Respir Crit Care Med. PubMed Scopus Google S. differences in lung and J Respir Crit Care Med. 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