Background: In the 2021 ERS/ATS technical standard, a significant bronchodilator response (sBDR) is defined as an increase in forced expiratory volume in 1 second (FEV1) or forced vital capacity of ?10% relative to the predicted value. However, the standard of 2005 stated an increase of ?200 mL and ?12% of the initial value.
Aim: This study aimed to compare sBDR classification based on the 2021 criteria with the 2005 criteria.
Methods: From 304 patients, aged ?18 years with a first time referral for a bronchodilator test, data were retrospectively derived from the Radboudumc, Nijmegen, the Netherlands (June-December 2022). Patients were classified as non-different when the 2005 and 2021 criteria on FEV1 resulted in same conclusion (sBDR+ or sBDR-). If both criteria resulted in different conclusions, patients were labelled as different. (Non)Parametric tests were performed to identify between group differences, and logistic regression was used to explore patient characteristics that might affect sBDR results.
Results: Based on the 2021 criteria 20.4% of the patients were classified as sBDR compared to 28.3% according to the 2005 criteria. In thirty patients (9.9%) classification of sBDR was labeled different (Table 1). Males (N=21/30) were 3.66 times more likely (CI=1.59-8.43, p=0.002) to be classified differently, while patients with higher baseline FEV1-values were 0.51 times less likely (CI=0.32-0.79, p=0.003).
| Table 1 | 2021 sBDR- | 2021 sBDR+ | Total |
|---|---|---|---|
| 2005 sBDR- | 215 | 3 | 218 |
| 2005 sBDR+ | 27 | 59 | 86 |
| Total | 242 | 62 | 304 |
Conclusion: Application of the 2021 criteria leads to a smaller number of people with sBDR. Mainly men and patients with lower baseline FEV1-values will be classified differently for sBDR.