Evaluating FEV1Q as a race-neutral measurement of lung function across three diverse populations in LMICs.

Abstract

Introduction The adjustment of lung function for ethnicity is controversial and has led to race-neutral approaches, such as forced expired volume in 1st second quotient (FEV1Q), which expresses FEV1 as a multiple of the theoretical lower limit of survival. It is unknown whether this lower limit is similar in diverse populations in different low- and middle-income countries (LMICs) or whether FEV1Q can accurately diagnose chronic obstructive pulmonary disease (COPD). This study aimed to evaluate the FEV1Q as a race-neutral measure of lung function in these regions. Methods This study utilised 10660 participants’ spirometry and anthropometric data, aged ≥40 years, collected from Uganda, Nepal, and Peru, with even sex and site distribution. The assessment included: whether 1st percentiles of absolute FEV1 were similar across these populations, assessing the FEV1Q diagnostic ability for 999 COPD cases, and estimating FEV1Q decline rates under several circumstances. Results The 1st percentiles of absolute FEV1 (L) were similar to the previously reported values of 0.5 L for males and 0.4 L for females in the COPD group, while these percentiles differed in the entire population. FEV1Q had discriminative accuracy in diagnosing COPD (AUC = 0.87). Estimation of FEV1Q decline under normal conditions demonstrated 1 unit/18 years, while it declined every 12.5 years for current smokers and every 17.5 years with biomass exposure. Discussion Although this study addressed the lack of diverse populations in which FEV1Q has been assessed, and presented several strengths, it did not include follow-up measurements of lung function which limit quantifying long-term outcomes; and ethnicity/race categories were assumed based on site. This highlights the need for future longitudinal studies to assess FEV1Q utility, and shed light on other respiratory conditions. Conclusion FEV1Q is a simple and promising race-neutral measure of lung function; however, further studies are required.