Comparison of Race-Neutral versus Race-Specific Spirometry Equations for Evaluation of Child Asthma

Rationale: Race-based estimates of pulmonary function in children could influence the evaluation of asthma in children from racial and ethnic minoritized backgrounds. Objectives: To determine if race-neutral (Global Lung Function Initiative [GLI]-Global) versus race-specific (GLI-Race-Specific) reference equations differentially impact spirometry evaluation of childhood asthma. Methods: The analysis included 8,719 children aged 5 to <12 years from 27 cohorts across the United States grouped by parent-reported race and ethnicity. We analyzed how the equations affected FEV₁, FVC, and FEV₁/FVC z-scores. We used multivariable logistic models to evaluate associations between z-scores calculated with different equations and asthma diagnosis, emergency department visits, and hospitalization. Measurements and Main Results: For Black children, the GLI-Global versus GLI-Race-Specific equations estimated significantly lower z-scores for FEV₁ and FVC but similar values for FEV₁/FVC, thus increasing the proportion of children classified with low FEV₁ by 14%. Although both equations yielded strong inverse relationships between FEV₁ and FEV₁/FVC z-scores and asthma outcomes, these relationships varied across racial and ethnic groups (P < 0.05). For any given FEV₁ or FEV₁/FVC z-score, asthma diagnosis and emergency department visits were higher among Black and Hispanic than among White children (P < 0.05). For FEV₁, GLI-Global equations estimated asthma outcomes that were more uniform across racial and ethnic groups. Conclusions: Parent-reported race and ethnicity influenced relationships between lung function and asthma outcomes. Our data show no advantage to race-specific equations for evaluating childhood asthma, and the potential for race-specific equations to obscure lung impairment in disadvantaged children strongly supports using race-neutral equations.