Table 2.

Approaches and Concerns Discussed in Working Groups

Approach	Potential Benefits	Concerns and Barriers
Short-term changes
Continue with race-specific equations but report strengths and limitations of incorporating race and ethnicity alongside PFT results to aid interpretation	Recognizes that race and ethnicity are not biological variables, are variably defined, and are not stable over time	Stops short of acting on the recognition of the limitations and evidence against race; risks medical harms
Change to reporting and interpreting PFTs with an average reference equation	–Consistent with scientific evidence supporting an average reference standard for mortality, incident lower pulmonary disease, and symptoms and lung structure in COPD – Potential for reduced medical harms; more persons of color with results near thresholds would be: – Further evaluated for pulmonary disease – Eligible for: – Pulmonary rehabilitation – Noninvasive ventilatory support – Earlier referral and listing for lung transplantation – Lung volume reduction surgery	– Uncertain effects and potential harms for persons of color with results near decision-making thresholds: – Persons of color with results near thresholds may have: – Reduced employment opportunity – More evaluation to be considered for surgical resection of lung cancer – Higher life insurance premiums in setting of chronic lung disease – Unknown if expected increased access to lung transplantation would increase harm for some patients – Uncertain effects and potential harms for White persons with results near decision-making thresholds: – Potential for underdiagnosis – Decreased eligibility for: – Pulmonary rehabilitation – Noninvasive ventilation – More easily meet eligibility criteria for lung cancer resection, employment, and lower life insurance premiums –Limitations of the proposed average reference equations, GLI Global –The number of potentially affected persons is unknown.
Report multiple predicted values	–Emphasizes the uncertainty inherent in applying reference equations –Allows choice of sensitivity and specificity for the clinical question –Option to report values from locally applicable race-specific equations, e.g., without race labels	–More burden on physicians –Challenging to make a choice without an adequate evidence base –Challenging to communicate results to ordering physicians and patients –Local predicted values may mask the impact of modifiable social and environmental factors on reduced pulmonary function
Report multiple LLNs (e.g., 2.5th, 5th, and 10th percentiles)
Measure pulmonary function in everyone between ages 20 and 25	–Baseline value for comparison if concern for pulmonary disease develops –Less dependence on choice of reference equation	–Cost –Conflict of interest, as laboratories and clinicians can make more money from more testing
Obtain more longitudinal data	–Detect a change within the expected range, detect disease sooner
Long-term changes
Develop a gray zone of uncertainty around the LLN	–Values lower than the lower bound of the gray zone more likely to be associated with disease –Values within the gray zone will be marked for the need to interpret with more caution and context	–No validated placement of the bounds of the gray zone –Values above the upper limit of the bound may still be found in disease if maximal attained pulmonary function in life is very high –An additional boundary to navigate is created
Use absolute FEV1, absolute FEV1 standardized to a power of height, or FEV1Q instead of reference equations	–Absolute FEV1 and FEV1 standardized to height equivalently classified ventilatory impairment in COPD without using race or age, compared with using predicted values (89) –Better prediction of survival (102–104) and COPD exacerbations (101) –Similar to the Social Security Administration’s use of PFTs for assessment of disability (95)	–Need data on performance beyond predicting mortality and in COPD, ventilatory impairment, and exacerbations –Limited diversity of populations studied –Clinicians do not have experience using these –Not applicable to pediatrics –FEV1Q derived from European Coal and Steel Community reference equations and should be validated in GLI
Use of sitting height, trunk:limb ratio (Cormic index), or other measures of chest size and limb length	–More precise expected values: sitting height explained up to 40% of the residual variation in lung size in one study (36) –May perform better in some applications such as detecting pathology arising after lung development	–Sensitive to socioenvironmental exposures (116–118) –Might normalize the effects of experiencing a harmful environment during lung growth –Variable results from studies with some finding body proportions are much less explanatory of racial differences in pulmonary function (33, 99, 105) –Larger and more diverse datasets with multiple measures of chest size have yet to be collected to determine whether they can be used to improve precision
Cessation of labeling individual results as “normal” or “abnormal” to convey the personalized approach necessary in PFT interpretation	–Use of individual z-scores within a continuous distribution of pulmonary function may be more helpful than binary “normal” and “abnormal” labels –Encourage development of models that combine PFTs and other data to predict specific outcomes –May remove need for reference equations	–Data and models to guide a personalized approach are lacking –Complex models built with machine learning algorithms risk perpetuating biases
Reference equations informed by genetic variants found to influence pulmonary function	–More precision for calculating expected pulmonary function	–Privacy, cost, blood collection –Increased precision has potential to lessen focus on clinical context in interpretation –Based on correlation and may not be causative
Adjust expected values on the basis of social and environmental factors	–More precision for calculating expected pulmonary function –Understanding of potentially modifiable risk factors in the population	–Demographic and socioeconomic characteristics need to be collected in a standardized way on a global level –Even when such data are available, their impact on pulmonary function and interactions with genetics need to be determined –If pulmonary function were adjusted for SES, this has the potential to obscure drivers of health disparities and could inappropriately normalize pulmonary function among those with adverse exposures

Definition of abbreviations: COPD = chronic obstructive pulmonary disease; FEV₁Q = FEV₁ in increments of a sex-specific absolute lung volume defined by the first percentile value found in people and patients with abnormal lung function; GLI = Global Lung Function Initiative; LLN = lower limit of normal; PFT = pulmonary function test; SES = socioeconomic status.