The impact of using non-birth sex on the interpretation of spirometry data in subjects with air-flow obstruction

Abstract

BACKGROUND: Sex is an important determinant of lung capacity and function. This study examined the impact of using non-birth sex on the interpretation of spirometry data in transgender subjects with air-flow obstruction. METHODS: This study was a retrospective analysis of anonymous spirometry data. Eighty adult male and 80 adult female subjects were chosen from the database via random sampling. FVC, FEV1, and FEV1/FVC were collected and analyzed. Differences in percent of predicted, Z scores, classification of disease severity, and the incidence of a value migrating above or below the lower limit of normal between sex assignments were examined. RESULTS: For born male subjects, percent of predicted for FVC and FEV1 were significantly higher when the female sex was used: 100.5% versus 118.5% and 78% versus 91.5%, respectively (P