African Americans have worse outcomes in chronic obstructive pulmonary disease (COPD).
Assess whether race-specific approaches for estimating lung function contribute to racial inequities by failing to recognize pathological decrements and considering them normal.
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 forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and other COPD outcomes, including COPD Assessment Test (CAT), St George’s Respiratory Questionnaire (SGRQ), CT percent emphysema, airway wall thickness (Pi10) and six-minute walk test (6MWT). 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 F test.
Using race-specific equations, African Americans were calculated to have better lung function than Non-Hispanic Whites ([FEV1] 76.2% vs. 71.3% predicted, P=0.02). Using universally-applied equations, African Americans were calculated to have worse lung function. Using NHW-H, FEV1 was 61.4%% versus 71.3%; (P<0.001). Using GLI-O, FEV1 was 69.4% versus 77.4% (P<0.001). Prediction errors from linear regression were less for universally-applied equations compared with race-specific equations when comparing FEV1 %predicted with CAT (P<0.01), SGRQ (P<0.01) and Pi10 (P<0.01). While African Americans had greater adversity (P<0.001), less adversity was only associated with better FEV1 in Non-Hispanic White participants (P-for-interaction=0.041).
Race-specific equations may under-estimate COPD severity in African Americans.