Effects of Spirometry Race-Neutral Values in a Pediatric Hospital System

Background: Reference values for spirometry vary by patient and are determined by the patient’s age, height, gender, and, previously, race. In 2023, ATS/ERS guidelines recommended using Global GLI (race-neutral) reference values. Research has focused on the effects of this change in various patient populations; however, the effects within the pediatric population remain unclear. We aimed to determine how moving to a race-neutral equation in our pediatric institutions affected our patients’ spirometry results. Methods: In an IRB-approved retrospective chat review performed between 1/2024 and 5/2024, we analyzed completed spirometry results for all patients. Patients who did not meet ATS standards for interpretation of spirometry were excluded. Spirometry results were analyzed using the ATS reference and GLI equations to observe FVC, FEV1, and Z-scores changes. Results: 1,663 patient spirometry results were reviewed (avg age 11.7 y). Six patients identified as Asian, 289 Black, 855 Caucasian, and 498 patients Mixed/Other. In the Asian, Black, and Mixed/Other reference values, predicted FVC and FEV1 increased, leading to a decrease in measured pre% pred, with the most significant decrease in the Black population (11.2% for FVC, 11% for FEV1 compared to 2.7% and 2.3% for Asian, 3.6% and 3.1% for Mixed/Other). In the Caucasian population, predicted values decreased leading to an increase in measured pre%pred by 4.4% for FVC and 3.8% in FEV1. There was no significant change in severity based on Z-scores for Asian and Mixed/Other populations. In the Black population, 46 patients (16%) went from normal to mild obstruction (Z-score -1.63 to -2.5), 21 patients (7.3%) went from mild to moderate (Z-score -2.5 to -4), and 1 patient (3.1%) went from moderate to severe (Z-score <-4). In Caucasian patients, 9 (1%) went from severe to moderate obstruction, 18 (2%) went from moderate to severe, and 42 (5%) went from mild to normal lung function. Conclusions: At our pediatric institution, the change from spirometry reference values with race factored to a global race-neutral reference equation led to an increase in the Black patient population having an interpretation and diagnosis of lung obstruction severity and a decrease in the Caucasian population’s interpretation and diagnosis of lung obstruction severity. Further research must be done regarding the clinical effects of this change on various populations, such as therapy changes, treatment cost, and additional testing.