Bronchodilator response in asthmatic patients without airway obstruction - to do or not to do?

<bold>Background:</bold> Despite being a controversial topic, the persistent positive bronchodilator response (BDR), even with regular treatment, has been considered a marker of worse asthma control according to GINA. <bold>Aims:</bold> To investigate the relation between BDR and gender, symptoms, therapy, eosinophilic inflammation and lung function (LF) in asthmatic patients without airway obstruction; To determine the role of FEV₁ as a predictor of BDR. <bold>Methods:</bold> Retrospective cross-sectional. The sample included 111 non-smoking asthmatic patients without airway obstruction. All patients underwent spirometry, plethysmography and bronchodilator test (ERS/ATS 2021). FENO was determined in 34 patients and the presence of eosinophilic inflammation was considered if ≥25 ppb. A cutoff point of 85% for FEV₁ was used to calculate sensitivity, specificity and odds ratio of positive BDR. <bold>Results:</bold> Negative BDR group (73%): 65.4% female, 74.1% regular treatment, 75.3% asymptomatic and 35.3% eosinophilic inflammation. Positive BDR group (27%): 63.3% female, 76.7% regular treatment, 86.7% asymptomatic and 20% eosinophilic inflammation. BDR was independent of gender, therapy, symptoms and eosinophilic inflammation. The negative BDR group had higher pre-BD FVC%, FEV₁%, FEV₁/FVC% and FEF´s% (<italic>p</italic><0.05) and lower RV% and RV/TLC% (p<0.01) compared to the group with positive BDR. The FEV₁≤85% criterion showed a sensitivity of 47% and specificity of 90%. The odds of positive BDR is 8 times higher in patients with FEV₁≤85% than those with FEV₁>85% (<italic>p</italic><0.05). <bold>Conclusion:</bold> BDR seems to be a determinant factor to optimize LF. Performing a BD in patients with FEV₁≤85% provide an added value, because they are more likely to have positive BDR.