The implications of adopting the race-neutral spirometry equations in the detection of airway obstruction in Chilean children with asthma.

OBJECTIVES

This study compared the performance of the GLI-2012 and GLI-2022 equations for detecting airway obstruction in Chilean asthmatic children.

METHODS

This cross-sectional analytical study compared the predicted values and z-scores for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and the FEV1/FVC ratio, calculated using the GLI-2012 Caucasian and race-neutral GLI-2022 equations, in 885 Chilean children with asthma aged 6-16 years. Airway obstruction was defined as an FEV1/FVC z-score of less than -1.64. Multivariable generalised estimating equations (GEE) logistic regression was used to identify the independent predictors of obstruction classification. This accounted for paired observations and adjusted for age, sex, and anthropometric covariates, including height-for-age and FVC z-scores.

RESULTS

Switching from the GLI-2012 equations to the race-neutral GLI-2022 equations increased the prevalence of airway obstruction from 12.9% to 14.0% (p = 0.002). Multivariable GEE analysis revealed that the GLI-2022 model was an independent predictor of obstruction (OR: 1.10; 95% CI: 1.02-1.19; p = 0.014). Meanwhile, height-for-age was a significant protective factor (OR: 0.72; 95% CI: 0.59-0.89; p = 0.003), while higher FVC z-scores were associated with an increased likelihood of an obstructed result (OR: 1.41; 95% CI: 1.12-1.77; p = 0.003).

CONCLUSIONS

Using the race-neutral GLI-2022 reference equations was associated with a higher detection of airway obstruction in Chilean children, resulting in unidirectional diagnostic reclassification. This transition is independent of sex but is significantly influenced by individual lung geometry and dysanapsis. These findings emphasise the importance of taking a nuanced, patient-specific clinical approach when implementing global reference standards.