Comparative study of bronchodilator responsiveness in a Greek pediatric and adult asthma cohort using 2021 and 2005 ATS/ERS guidelines

<bold>Aim:</bold> To compare the concordance of Bronchodilation Reversibility Testing (BDR) according to the two ERS/ATS definitions (2005 vs 2021) in a cohort of Greek adult and pediatric asthma patients. <bold>Methods:</bold> Consecutive, anonymized data recorded during 2022-2023 in one paediatric and one adult asthma outpatient clinic of a tertiary hospital of Northern Greece were retrospectively analysed. Patients with a first-time referral for a bronchodilator test were included. Chi-square test was utilised for group comparisons of BDR 2005 vs BDR 2021 tests in both cohorts. <bold>Results:</bold> Data were available for 274 patients, 190 adults and 84 children, aged 4.3 to 80 years old. Out of 170 BDR2021 negative (−) patients, 11 (6.5%) were BDR2005 positive (+). Of 174 (63.5%) who were BDR2005-, 15 (8.6%) were BDR2021+ (p<0.001). Dividing into subgroups, 65 (34%) adults and 24 (29%) children were BDR+ by both definitions. The two criteria led to discordant results in 13% and 7.9% of children and adults, respectively. More tests were classified as BDR+ using the 2021 criteria compared to 2005 in adults (n = 80/190, 42 % vs. 65/190, 34%; p =0.01) while the opposite trend was observed in children (n= 24/84, 29% vs. 35/84, 42%; p<0.001) (Table). <bold>Conclusions:</bold> In our cohort, the 2021 recommendation for BDR interpretation led to a small but significant reclassification in the number of BDR+ tests, with discrepancies assessed between adult and children group. Larger population data are needed. <table-wrap><object-id>erj;64/suppl_68/PA2595/TB1</object-id><object-id>T1</object-id><object-id>TB1</object-id><table><colgroup><col></col><col></col><col></col><col></col></colgroup><tbody><tr><td></td><td>Total Sample (N=274)</td><td>Adults (n= 190)</td><td>Children (n=84)</td></tr><tr><td></td><td>BDR2021+%</td><td>BDR2021-%</td><td>BDR2021+ %</td><td>BDR2021- %</td><td>BDR2021+%</td><td>BDR2021-%</td></tr><tr><td>BDR2005+%</td><td>32.5</td><td>4</td><td>34</td><td>0</td><td>29</td><td>13</td></tr><tr><td>BDR2005- %</td><td>5.5</td><td>58</td><td>8</td><td>58</td><td>0</td><td>58</td></tr><tr><td>Total%</td><td>38</td><td>62</td><td>42</td><td>58</td><td>29</td><td>71</td></tr></tbody></table></table-wrap>