Figure 2.

Reclassification of African American (AA) participants with chronic obstructive pulmonary disease (COPD) and undiagnosed participants using different prediction equations. (A1–A3) Each panel demonstrates the shifts of participants from the reference NHANES (National Health and Nutrition Examination Survey) AA race-specific classification to an alternative prediction equation (Global Lung Function Initiative [GLI] Other, GLI Global, and the NHANES non-Hispanic White (NHW) race-specific “race-reversed”). The overall pattern shows that the AA race-specific equations classify individuals as less severely diseased compared with other equations. GLI Other and GLI Global are similar, but there were slightly more reclassifications under GLI Global (198 vs. 210 out of a total of 1,050 AA participants classified as having COPD [approximately 20%]). (A1) GLI Other classifications, whereby 89 AA participants were reclassified in Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 2. Similar reclassification occurred at each GOLD stage, and in all cases, participants were reclassified to worse disease stages. (A2) GLI Global equations and their impact on classification, with 101 participants reclassified from GOLD stage 1 to GOLD stage 2. (A3) The greatest impact was noted using race-reversed equations and applying the NHW NHANES equations to AA participants. In this scenario, 131 of the initial 191 GOLD stage 1 participants were reclassified to GOLD stage 2. The trend continued with a large number of AA participants reclassified from GOLD stage 2 to GOLD stage 3, while the reclassifications to more advanced disease from GOLD stage 3 to GOLD stage 4 were fewer. (B1–B3). The proportion of AA participants (70%) who did not meet the fixed-ratio criteria (FEV₁:FVC < 0.7) for COPD was greater than that of NHW (49%) in the COPDGene cohort and was consequent to the effect of lower FVC values in a portion of the AA group, as previously reported (21). Thus, these participants could not be reclassified into any of the GOLD stages on the basis of different race-specific equations and could only move between preserved ratio impaired spirometry (PRISm) and GOLD stage 0 groups, as described in our extended classification. As for the COPD-diagnosed participants, the different prediction equations resulted in large numbers of participants being reclassified as sicker (moving to PRISm), with the GLI Other equations (B1) having the fewest (n = 375) reclassified to PRISm; GLI Global equations had 472 participants reclassified to PRISm (B2), and race-reversed NHANES equations had 774 participants (43% of the GOLD stage 0 AA participants) reclassified to PRISm. COPDGene = Genetic Epidemiology of Chronic Obstructive Pulmonary Disease.