D2.92 - Comparison of responsiveness to bronchodilators using the 2021 or 2005 ATS/ERS guidelines: bicenter retrospective study
Background
In ERS/ATS 2021 interpretive strategies for routine pulmonary function testing, a positive bronchodilator response (BDR) was updated as a change >10% from the predicted value of forced expiratory volume in 1 second (FEV1), in contrast to the previous 2005 guidelines that recommended a change of 200 ml and 12% from baseline in FEV1.
The new criteria consider each patient’s individual characteristics measuring the change relative to the predicted value rather than using a standard cut-off point, increasing the specificity of the test and allowing for more tailored treatment. The aim of our study was to explore the differences between the 2005 and 2021 ERS/ATS criteria.
Method
We conducted a bicentric retrospective study evaluating BDR test collected from the Allergology and Clinical Immunology Unit in Monserrato Hospital (Cagliari) and in Humanitas Research Hospital (Milan), between January 2020 and October 2024.
BDR results defined by the 2005 and 2021 ERS/ATS criteria were referred 2005-BDR and 2021-BDR. Positive and negative results were referred to as BDR+ and BDR-, respectively.
Results
A total of 1794 BRDs were included in the analysis. Among the 1794 tests, 540 (23%) were BDR+ by one or both definitions.
The number of 2005-BDR+ FEV1 and 2021-BDR+ FEV1 were 512 (52%) and 482 (48%), respectively. Of the total of BDR+ FEV1, 81 were discordant, this means positives for only one of the two guidelines. Of these 81 discordant tests, 57 (70%) were 2005 BDR+ and 24 were 2021 BDR+ (30%).
Conclusion
Comparing positive bronchodilator responses (BDR+) according to the 2005 and 2021 ERS/ATS criteria, it was found that the 2021 criteria identified fewer positive BDR cases.
Among the 81 discordant cases (positive according to only one of the guidelines), the majority (70%) were BDR+ according to the 2005 criteria but not the 2021 criteria.
These findings suggest that the updated 2021 ERS/ATS criteria are more specific and conservative in defining a positive BDR. The 2005 criteria may capture more borderline or marginal cases as positive, while the 2021 criteria are stricter and likely reflect more clinically significant changes in lung function.
