Impact of the ERS/ATS 2021 Guidelines for Lung Function Interpretation

This study investigates how the recently published ERS/ATS guidelines for lung function interpretation (Stanojevic 2021) affect patient classification compared to the previous (Pellegrino 2005). 1325 subjects admitting to secondary respiratory practice (244 healthy, 1081 disease) were classified by both guidelines via an algorithm (based on pattern, severity, and bronchodilator response (BDR)). We observed limited impact in the pattern description: 100/1325 subjects are classified to a novel category for the lung function (Nonspecific category, previously obstructive with a normal FEV1/FVC, Fig 1A), and 14 for the diffusion (Fig 1C). Z-scores to define severity introduced a large shift in classes ranging from mild, moderate to severe obstruction/restriction, with milder labels based on FEV1 and TLC, but opposite shifts when DLCO was taken. The new BDR is stricter with 27% of the significant subjects changing to insignificant BDR, particular with lower FEV1 (Fig 1D). Figure. Comparison of 2005 and 2021 guidelines for lung function test interpretation applied on 1325 different subjects. Panel A/Lung function patterns; Panel B/FEV1/TLC severity Panel C/Diffusion severity; D/ Bronchodilator response. The 2021 guidelines add more categories to distinguish lung function impairments. The severity labels substantially change and BDR is stricter in a respiratory disease population. The impact on current disease management should be investigated.