In the Internal Helen Luo and her team have presented significant evidence regarding the effects of implementing race‐neutral lung function reference equations within a substantial Australian cohort. 1 By analysing data from more than 6000 adults evaluated in a tertiary respiratory laboratory, the researchers compared race‐neutral equations with race‐specific ones from the Global Lung Function Initiative. They found a high level of agreement in diagnostic classification, along with notable changes in the prevalence and severity of ventilatory defects among different ethnic groups. These results carry important clinical implications, especially regarding potential reclassification of obstructive and restrictive patterns. Nonetheless, interpreting these findings requires caution due to several methodological aspects that could affect estimates of disease prevalence and severity.
A key methodological issue concerns how restrictive ventilatory defects are defined in the study. The researchers identified restriction by noting a decrease in forced vital capacity (FVC) below the lower limit of normal; however, relying solely on spirometry is inadequate for confirming true restriction. According to the interpretive standards set by the American Thoracic Society and the European Respiratory Society, a conclusive diagnosis of restrictive lung disease requires evidence of reduced total lung capacity (TLC), as a low FVC may reflect air trapping, insufficient effort or obesity rather than genuine parenchymal restriction. 2 Additionally, clinical research has shown that restrictive patterns identified through spirometry have limited diagnostic precision, with many cases not being confirmed when lung volumes are assessed, highlighting the risk of misclassification when FVC is used alone. 3 Given that the present study reports substantial changes in the prevalence and severity of restrictive ventilatory defects following the adoption of race‐neutral equations, this definitional limitation may have influenced the magnitude of observed reclassification across ethnic groups.
A further methodological issue concerns the study population, which was sourced from a tertiary respiratory laboratory cohort of individuals referred for assessment of respiratory symptoms or suspected obstructive airway disease, rather than a sample representative of the general community. This raises potential spectrum (selection) bias, where disease prevalence and diagnostic accuracy may vary between clinical populations and the general population. In such contexts, individuals tend to have a higher pre‐test likelihood of respiratory disease, which could affect the observed prevalence of ventilatory defects and the extent of reclassification when different reference equations are applied. Evidence from clinical spirometry cohorts shows that disease estimates and diagnostic classification vary depending on population context, underscoring the limited generalisability of findings from selected populations. 4 Therefore, the observed impact of race‐neutral equations may not fully reflect their effects in broader epidemiological settings.
In conclusion, while the work provides valuable insights into the influence of race‐neutral lung function equations, it should be interpreted in light of the aforementioned methodological constraints. Future studies should employ population‐based cohorts to improve generalisability, incorporate TLC assessments to confirm true restriction and perform long‐term studies linking reclassification to clinical outcomes to better understand the real‐world implications of adopting race‐neutral reference equations.
Disclosure
The author used an artificial intelligence tool (ChatGPT, OpenAI) solely for language editing and grammatical refinement. The intellectual content, interpretation and conclusions of the manuscript are entirely the author's own, and the AI tool had no role in generating or altering the scientific content.
Data availability statement
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.
References
- 1. Luo H, Finlay P, Cestnik A, Nirmalan K, Moncrieff L, Hamilton GS et al. Implications of race‐neutral equations on interpretation of lung function in Australia. Intern Med J 2026; 56: 1011–1018. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Pellegrino R, Viegi G, Brusasco V, Crapo RO, Burgos F, Casaburi R et al. Interpretative strategies for lung function tests. Eur Respir J 2005; 26: 948–968. [DOI] [PubMed] [Google Scholar]
- 3. Wesołowski S, Boros P. Wykrywanie restrykcyjnego typu zaburzeń wentylacji w spirometrii— czy FEV1/FVC musi być podwyższone? [Restrictive pattern in spirometry: does FEV1/FVC need to be increased?]. Pneumonol Alergol Pol 2011; 79: 382–387. [PubMed] [Google Scholar]
- 4. Bradley C, Alexandris P, Baldwin DR, Booton R, Darby M, Eckert CJ et al. Measuring spirometry in a lung cancer screening cohort highlights possible underdiagnosis and misdiagnosis of COPD. ERJ Open Res 2023; 9: 00203‐2023. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.