Clinical value of bronchodilator response for diagnosing asthma in steroid-naïve adults

Spirometry and testing for bronchodilator response have been recommended to detect asthma, and a bronchodilator response (BDR) of ≥12% and ≥200 mL has been suggested to confirm asthma. However, the clinical value of bronchodilation tests in newly diagnosed steroid-naive adult patients with asthma remains unknown. We evaluated the sensitivity of BDR in FEV1 as a diagnostic test for asthma in a real-life cohort of participants in the Seinajoki Adult Asthma Study (SAAS). In the diagnostic phase, 369 spirometry tests with bronchodilation were performed for 219 steroid-naive patients. The fulfilment of each test threshold was assessed. According to the algorithm of the National Institute for Health and Care Excellence, we divided the patients into obstructive (FEV11/FVC