FEV1Q as a race-neutral assessment of lung function in Nepal, Peru and Uganda

Background: FEV1Q (Forced Expiratory Volume in 1 s Quotient) is a race-neutral expression of lung function. The validity and utility of FEV1Q across Global South populations has not been previously explored. // Methods: We conducted a post-hoc analysis of data from the Global Excellence in COPD Outcomes-1 (GECo1 and GECo2) studies in which a random age- and sex-stratified population of 10 709 people were recruited in Nepal, Peru and Uganda. The FEV1 first percentile (used to derive FEV1Q) was estimated in those with COPD by site and sex. We examined associations between FEV1Q, risk factors and respiratory morbidity. We estimated the rate of decline in FEV1Q. We evaluated the discriminative accuracy of FEV1Q in diagnosing COPD. // Findings: The first percentile FEV1 in those with COPD at 0·43 L in women and 0·52 L in men is similar to those previously used to calculate FEV1Q. Lower FEV1Q was associated with older age, lower socioeconomic status, shorter height, and greater smoking pack-years. We estimated that decline in FEV1Q with age was 0·65 (95%CI: 0·64; 0·67) units/10 years, more rapid in those continuing to smoke at 0·82 (95%CI: 0·77; 0·87) units/10 years. FEV1Q was lower in those with prior respiratory hospitalizations and impairment in daily activities due to respiratory disease, and associated with future hospitalization risk in the GECo2 study. Pre-bronchodilator FEV1Q had reasonable diagnostic accuracy for COPD (AUC 0·87(95%CI:0·85-0·88)), similar to pre-bronchodilator FEV1% predicted (AUC 0·88(95%CI:0·87-0·90)). // Interpretation: Our data support the validity and utility of FEV1Q as a race-neutral approach to lung function assessment in diverse settings, including the Global South where the burden of lung disease is greatest. // Funding: This study was funded by the Medical Research Council (grant MR/P008984/1) under a Global Alliance for Chronic Diseases call. JRH is funded by the NIHR (project reference 303125) using UK international development funding from the UK Government to support global health research. The views expressed in this publication are those of the authors and not necessarily those of the NIHR or the UK government.