Frequency and characteristics of different clinical phenotypes of chronic obstructive pulmonary disease

SETTING: Clinical phenotypes of chronic obstructive pulmonary disease (COPD) identify patients with common characteristics. OBJECTIVES: To investigate the distribution of four different COPD phenotypes: non-exacerbators, patients with asthma-COPD overlap syndrome (ACOS), exacerbators with chronic bronchitis and those without, we analysed the impact of COPD on quality of life (HRQoL), and on anxiety and depression in these phenotypes. DESIGN: Observational, multicentre study conducted among 3125 COPD patients recruited from out-patient clinics in Barcelona, Spain. Phenotyping was performed based on the clinical information available. The COPD Assessment Test and EuroQoL-5 Dimensions questionnaire were used to evaluate HRQoL; patient mood was evaluated using the Hospital Anxiety and Depression Scale (HADS). RESULTS: The distribution of phenotypes was as follows: 60.6% non-exacerbators, 15.9% ACOS patients, 19.3% exacerbators with chronic bronchitis and 4.3% exacerbators without chronic bronchitis. Non-exacerbators had milder COPD, whereas exacerbators presented with the most severe disease, with little difference between those with and those without chronic bronchitis. ACOS patients were more frequently female with better lung function, but more impaired HRQoL and greater anxiety and depression, than non-exacerbators. CONCLUSIONS: Almost two thirds of COPD patients are non-exacerbators, and 15.9% have ACOS. Different phenotypes showed different demographic and clinical characteristics as well as impact on HRQoL and mood.