Race-neutral spirometry reclassification in self-identified Black and White patients.

BACKGROUND

Recent consensus guidelines endorsed using a Global Lung Function Initiative (GLI Global) race-neutral approach to interpret spirometry. This study aims to examine how spirometry results using GLI Global reference equations correlate with patient healthcare utilisation and outcomes in a real-world cohort of patients.

METHODS

Pulmonary function tests (PFTs) were analysed via race-specific and GLI Global approaches, respectively, using a 2010-2020 retrospective cohort study of spirometry tests. An abnormally low result for either forced vital capacity (FVC) or forced expiratory volume in 1 s (FEV1) was defined as a z-score <-1.645. The 1-year pulmonary medication prescription, outpatient visit, emergency department (ED) visit or hospitalisation, as well as all-cause mortality were evaluated.

RESULTS

Out of the total cohort of 6107 tests, 530 (9%) and 595 (10%) results were re-classified when switching from race-specific to race-neutral for FEV1 and FVC, respectively. Compared with patients whose lung function was consistently in the normal range (the control group), Black patients who were re-classified with an abnormally low FEV1 had higher healthcare utilisation including pulmonary medication prescriptions, ED visits and worse outcomes such as hospitalisation. White individuals whose FEV1 was re-classified as normal also had worse outcomes including higher mortality than the consistently normal group. Similar results were obtained when analysing FVC.

CONCLUSIONS

We conclude that both Black and White individuals whose FEV1 and FVC were re-classified had worse outcomes compared with those who remained normal. Clinical context and judgment must be used when considering any lung function result near arbitrary thresholds of normal.