Implications of removing race from spirometry reference equations in children with asthma.

Background: The Global Lung Initiative (GLI) recently developed a race-neutral reference equation in 2022 (GLI-2022); however, the implications of its use in children with asthma, especially Latino children, have not been extensively studied.

Objective: Assess the difference in spirometry results, asthma severity and airways obstruction classification for African American (AA), Latino and White children with asthma after implementing GLI-2022.

Methods: This retrospective cross-sectional study evaluated the first spirometry performed by children with asthma aged 5-17 years between 01/01/2018 and 12/31/2023. Z-scores and percent predicted (pp) values for forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and FEV1 /FVC were calculated using GLI-2022 and race-adjusted Global Lung Function Initiative 2012 (GLI-2012) equations.

Results: A total of 7138 children: 3543 AA, 2795 White, and 800 Latino were included (median age = 10.3 years). FEV1 z-score median difference was -0.872, -0.360, and +0.267 in AA, Latino, and White children, respectively (p < 0.0001) after implementing GLI-2022. FVC z-scores, ppFEV1 and ppFVC values showed similar patterns. Adopting GLI-2022 worsened asthma severity (based on ppFEV1) and degree of airways obstruction (based on FEV1 z-score) classifications in AA children, improved them in White children, and did not affect Latino children.

Conclusion: Implementing GLI-2022 impacted asthma severity and airway obstruction classifications and resulted in a lower FVC and FEV1 in AA and Latino children and greater values in White children. Using GLI-2022 may uncover more cases of underdiagnosed asthma in AA and Latino children, which may contribute to alleviating disparate asthma outcomes.