D3.159 - Early Bronchodilator Response in Asthma: When Is Testing Really Necessary?

Airflow variability is a hallmark of asthma, and the early bronchodilator response (BDR) test plays an important role in supporting the diagnosis. The test is performed by repeating spirometry 15 minutes after short-acting β₂-agonist inhalation, with a ≥12% and ≥200 mL increase in FEV₁ and/or FVC considered a significant response. However, routine use of BDR testing in all asthma patients may lead to unnecessary workload and inefficient use of healthcare resources.

This study aimed to determine in which asthma patients early bronchodilator response testing is most appropriate, based on baseline FEV₁ and FEV₁/FVC values, in order to optimize test utilization and avoid unnecessary testing.

A total of 100 asthma patients were included. Patients were evaluated according to age, sex, pre- and post-bronchodilator FEV₁ and FEV₁/FVC values, and peripheral blood eosinophil counts. Patients were grouped based on FEV₁ and FEV₁/FVC thresholds (<80% and ≥80%). Early bronchodilator response positivity was compared between groups using appropriate statistical tests.

Early bronchodilator response did not differ significantly according to sex. Patients aged 35–55 years showed a significantly higher bronchodilator response compared with other age groups (p = 0.044). Patients with normal baseline FEV₁ values demonstrated significantly lower early bronchodilator response rates compared with those with reduced FEV₁ (p < 0.001). Similarly, patients with normal baseline FEV₁/FVC ratios had significantly lower bronchodilator response compared with patients with reduced FEV₁/FVC values (p = 0.038). No significant association was observed between peripheral blood eosinophil count and bronchodilator response positivity.

Early bronchodilator response testing should primarily be considered in asthma patients with FEV₁ <80% and/or FEV₁/FVC <80%. Restricting testing to selected patient groups may improve clinical efficiency, reduce unnecessary testing, and allow more rational use of physician time and healthcare resources, while preserving diagnostic accuracy in asthma.