Table. 1—

Risk factors for frequent exacerbations(more than two per year) in patients with chronic obstructive pulmonary disease

Risk factors
Increased age
Severity of FEV1 impairment
Chronic bronchial mucus hypersecretion
Frequent past exacerbations
Daily cough and wheeze
Persistent symptoms of chronic bronchitis
Comorbid conditions: mainly cardiovascular disease
  • FEV1: forced expiratory volume in 1 s. Adapted from [11–14, 17, 18].