Implications of reference equations for interpretation of spirometry in three African countries: a cross-sectional study.

Background: The Global Lung Function Initiative (GLI) and American Thoracic Society recently endorsed a race-composite spirometry reference equation ("GLI Global"). Africa (outside North Africa) is not represented in the underlying dataset; GLI Global has not been evaluated in the region. We evaluated the fit and diagnostic implications of GLI and African (identified by scoping review) reference equations in three East/Southern African countries. Methods: Among healthy participants from a tuberculosis household contact cohort study in Mozambique, Tanzania and Zimbabwe (age ≥10 years) with post-bronchodilator spirometry we calculated forced expiratory volume in 1 s (FEV Results: In total, 806 healthy people had good-quality post-bronchodilator spirometry. Across GLI equations, "African American" fitted best (mean±sd FEV Conclusions: Reference equations have clinical and public health implications that demand careful consideration, particularly in resource-constrained environments. Use of GLI Global may result more people being identified as having lung function impairment. Further work that includes clinical outcomes is needed to ensure that GLI Global is globally representative. The key limitation of this work is the potential for people with undiagnosed respiratory disease to have been included in the analysis.