Do Patients with Chronic Bronchitis but No Spirometric Obstruction Have COPD?

Chronic bronchitis is defined as presence of cough and phlegm for at least 3 months for ≥2 consecutive years. Chronic obstructive pulmonary disease (COPD) requires presence of obstruction, as defined by a postbronchodilator FEV₁/FVC (forced expiratory volume in 1 second/forced vital capacity) ratio of less than 0.7. To examine the prognosis for patients with chronic bronchitis but no obstruction, researchers pooled data on from five U.S. cohorts with more than 22,000 patients, half of whom were current or former smokers.

Nonobstructive chronic bronchitis was diagnosed in 2.7% of ever smokers; these patients had loss of FEV₁ and FVC (but no change in FEV₁/FVC ratio) and more lower respiratory disease–related hospitalizations and mortality dur…