title: Characterisation of the overlap COPD-asthma phenotype. Focus on physical activity and health status.
abstract: BACKGROUND
  Patients with COPD may share some clinical characteristics with asthma sufferers. This phenotypic overlap between COPD and asthma is not yet well characterised.
  
  
  METHODS
  We have analysed data from the EPI-SCAN study, an epidemiological, population-based study in Spain that included 3885 (40 to 80-year-old) subjects in order to investigate the clinical and systemic inflammatory characteristics of COPD patients previously diagnosed with asthma. Generic and COPD-specific quality of life, as well as physical activity, were also assessed through standardised and validated questionnaires.
  
  
  RESULTS
  A total of 385 (10.1%) subjects were diagnosed with COPD, 67 (17.4%) being classified with the COPD-asthma overlap phenotype. Such patients were more likely to have dyspnea and wheezing (p<0.001 in both comparisons) and more frequent exacerbations (p<0.001). No differences in systemic inflammatory markers were observed except for lower NOx concentrations in overlap patients (p=0.013). This overlap phenotype significantly worsened specific quality of life (11.1 units on the St. George's Respiratory Questionnaire (SGRQ), 95%CI: 4.88-17.36) and reduced physical activity (3.49 units on the London Chest Activities of Daily Living (LCADL) scale, 95%CI: 1.06-5.94).
  
  
  CONCLUSIONS
  In this population-based study, 17.4% of the individuals identified with COPD had an overlap COPD-asthma phenotype. This patient subgroup had more dyspnea, wheezing, exacerbations, worse respiratory-specific quality of life, and reduced levels of physical activity. Specific interventions may be required to adequately care for this subgroup of patients.
authors.affiliation: Pneumology Department, Hospital Universitari Vall d'Hebron, Pg Vall d'Hebron 119-129, 08035 Barcelona, Spain. marcm@separ.es
authors.forename: Marc
authors.initials: M
authors.lastname: Miravitlles
authors.forename: Joan B
authors.initials: JB
authors.lastname: Soriano
authors.forename: Julio
authors.initials: J
authors.lastname: Ancochea
authors.forename: Luis
authors.initials: L
authors.lastname: Muñoz
authors.forename: Enric
authors.initials: E
authors.lastname: Duran-Tauleria
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Sánchez
authors.forename: Víctor
authors.initials: V
authors.lastname: Sobradillo
authors.forename: Francisco
authors.initials: F
authors.lastname: García-Río
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology / Q000534:rehabilitation; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D010641:Phenotype; D011594:Psychometrics; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology / Q000534:rehabilitation; D011788:Quality of Life; D012720:Severity of Illness Index; D013030:Spain / Q000453:epidemiology; D014797:Vital Capacity / Q000502:physiology
chemical_list: D015415:Biomarkers