Evidence base is limited
“Although evidence demonstrates differences in lung function between racial/ethnic groups, the premise that dividing lung function interpretation up by racial/ethnic background is helpful in the clinical setting is not a proven one.” The authors cited some evidence that lung function interpretation without consideration of race/ethnicity has superior prognostic ability. In addition, research has shown only a weak relationship between lung function and work ability, according to the authors. More appropriate ways of assessing expected lung function for an individual in the absence of a diagnoses are under study.
Offering an alternative
As an alternative to race, Dr. Bhakta and colleagues proposed using a range of values that include individuals across many global populations while still adjusting for sex, age, and height. The resultant value would represent a diverse population average and widen the limits of normal that can be expected in otherwise-healthy people.
The approach would include PFTs with other factors for clinical decision-making, but would allow clinicians and patients to appreciate the limitations of interpretation based on comparison to reference values. However, such an approach may miss pathophysiologically reduced lung function in some individuals, in which case lifesaving therapies, such as chemotherapy, lung cancer resection, and bone marrow transplantation could be withheld. In other instances the consequence would be overtesting and diagnosis, they acknowledged.
The authors further discussed general concerns about the use of race in interpretation of PFTs, addressing limits/considerations as well as knowledge and practice gaps.
For example, one particular concern involves the fact that race does not capture acculturation and mixed ancestry. The limit/consideration is the need to discover mechanisms for differences and to suggest societal interventions, and the knowledge gap pertains to ignorance regarding mechanisms leading to differences in lung function.
For the concern that race is not a proxy for an individual’s genetics, the limit/consideration is that race captures only some genetics and the gap is the need for better genetic information. As an antidote to over reliance on lung function thresholds (without supporting data), they urged outcomes-based standards rather than comparisons with reference populations.
New thinking needed
Dr. Bhakta and colleagues pointed out that the forced expiratory volume in 1 second/forced vital capacity ratios important for diagnosis of obstructive lung disease are similar between racial/ethnic categories, underscoring the need for education about limitations of thresholds and reference values with regard to race, particularly as they are used to detect mild disease.
Ignoring race, on the other hand, can lead to unnecessary testing and treatment (with concomitant side effects), and anxiety.
“Reporting through race-based algorithms in the PFT laboratory risks portraying racial disparities as innate and immutable. By anchoring on the improved prediction of lung function from racial/ethnic-specific reference equations, we miss how the significant residual variation still leaves much uncertainty about the expected value for an individual,” the authors concluded. “Given their origin and historical and current use in society, these racial/ethnic labels are better used to identify the effects of structural racism on respiratory health in research and ensure adequate representation in research, rather than in clinical algorithms.”
One of the authors is a speaker for MGC Diagnostics. The others indicated that they had no relevant disclosures.