Who gets in? Rethinking clinical trial access in the era of race-neutral pulmonary function

Abstract

Pulmonary function tests are essential diagnostic tools in respiratory medicine, with interpretation dependent on predicted normal values derived from population-based reference equations. Historically, these equations included race as a variable, based on the assumption that individuals from different racial backgrounds have innate physiological differences in lung function. However, this practice has come under increasing scrutiny, as emerging evidence shows that observed racial differences are not due to inherent anatomical variation, such as chest size or airway diameter, but rather reflect the cumulative impact of structural inequities, including limited access to clean air, nutritious food, quality healthcare and safe housing.1 In 2022, the Global Lung Function Initiative (GLI) introduced new race-neutral reference equations for spirometry, developed using global, multiethnic data without race-based adjustment factors (GLI global).2 This marked a major departure from long-standing clinical practice and reflected growing recognition that race is a social construct—not a biological determinant—and should not be used to define physiological norms. In 2023 and 2024, the shift gained momentum, with endorsements from leading organisations including the American Thoracic Society and the European Respiratory Society.3 While eliminating race from predictive models is intended to enhance diagnostic accuracy and promote equity, this transition presents important clinical and research challenges. The use of race-neutral equations …