According to a study published in International Journal of Chronic Obstructive Pulmonary Diseasebronchiectasis patients with poor response to a first bronchodilator test unexpectedly improved their lung function after long-term treatment with a bronchodilator.

Bronchodilator use is currently recommended only for patients who improve their lung function after an initial test with a short-acting bronchodilator.

Among the 166 patients analyzed, 57 (34%) responded to long-term bronchodilator treatment and improved their lung function; of these patients, only 22 had a positive BDR at the beginning of the study.