Reconsidering the Utility of Race-Specific Lung Function Prediction Equations

Abstract

<b>Rationale:</b> African American individuals have worse outcomes in chronic obstructive pulmonary disease (COPD). <b>Objectives:</b> To assess whether race-specific approaches for estimating lung function contribute to racial inequities by failing to recognize pathological decrements and considering them normal. <b>Methods:</b> In a cohort with and at risk for COPD, we assessed whether lung function prediction equations applied in a race-specific versus universal manner better modeled the relationship between FEV₁, FVC, and other COPD outcomes, including the COPD Assessment Test, St. George's Respiratory Questionnaire, computed tomography percent emphysema, airway wall thickness, and 6-minute-walk test. We related these outcomes to differences in FEV₁ using multiple linear regression and compared predictive performance between fitted models using root mean squared error and Alpaydin's paired <i>F</i> test. <b>Measurements and Main Results:</b> Using race-specific equations, African American individuals were calculated to have better lung function than non-Hispanic White individuals (FEV₁, 76.8% vs. 71.8% predicted; <i>P</i> = 0.02). Using universally applied equations, African American individuals were calculated to have worse lung function. Using Hankinson's Non-Hispanic White equation, FEV₁ was 64.7% versus 71.8% (<i>P</i> < 0.001). Using the Global Lung Initiative's Other race equation, FEV₁ was 70.0% versus 77.9% (<i>P</i> < 0.001). Prediction errors from linear regression were less for universally applied equations compared with race-specific equations when examining FEV₁% predicted with the COPD Assessment Test (<i>P</i> < 0.01), St. George's Respiratory Questionnaire (<i>P</i> < 0.01), and airway wall thickness (<i>P</i> < 0.01). Although African American participants had greater adversity (<i>P</i> < 0.001), less adversity was only associated with better FEV₁ in non-Hispanic White participants (<i>P</i> for interaction = 0.041). <b>Conclusions:</b> Race-specific equations may underestimate COPD severity in African American individuals.Clinical trial registered with www.clinicaltrials.gov (NCT01969344).