Are Bronchodilators Effective in Symptomatic Smokers with Normal Spirometry?

The diagnosis of chronic obstructive pulmonary disease (COPD) requires a postbronchodilator forced expiratory volume in 1 second to forced vital capacity (FEV₁/FVC) ratio of <0.7. However, patients with normal spirometry can have small airway disease, classic emphysematous changes on imaging, or symptoms consistent with chronic bronchitis (i.e., presence of cough and sputum for >3 months for 2 consecutive years).

U.S. researchers enrolled 535 patients with respiratory symptoms (COPD Assessment Test score, ≥10 on a 40-point scale) and at least a 10-year smoking history but no evidence of airflow obstruction. Patients were randomized to inhaled indacaterol (a long-acting β₂-agonist) plus glycopyrrolate (a long-acting antimuscarinic agent) or t…