title: Asthma-COPD overlap syndrome (ACOS) vs 'pure' COPD: a distinct phenotype?
abstract: BACKGROUND
  Some studies suggest that asthma-COPD overlap syndrome (ACOS) is associated with worse outcomes than chronic obstructive pulmonary disease (COPD). The goal of this study was to further explore the clinical characteristics and survival of patients with ACOS identified in a real-life cohort of patients with COPD.
  
  
  METHODS
  Data from the French COPD cohort 'INITIATIVES BronchoPneumopathie Chronique Obstructive' (n = 998 patients) were analyzed to assess the frequency of ACOS defined as a physician diagnosis of asthma before the age of 40 years and to analyze its impact. Univariate analyses were performed to assess the relationship between ACOS and sociodemographic characteristics, risk factors (smoking, occupational exposure, atopic diseases), symptoms (chronic bronchitis, dyspnea-modified Medical Research Council scale and baseline dyspnea index), quality of life (QoL), mood disorders, exacerbations, comorbidities, lung function, prescribed treatment, and survival.
  
  
  RESULTS
  ACOS was diagnosed in 129 patients (13%). In multivariate analyses, ACOS was associated negatively with cumulative smoking (odds ratio [OR]: 0.992; 95% CI 0.984-1.000 per pack-year) and positively with obesity: OR: 1.97 [1.22-3.16], history of atopic disease (hay fever: OR: 5.50 [3.42-9.00] and atopic dermatitis: OR 3.76 [2.14-6.61]), and drug use (LABA + ICS: 1.86 [1.27-2.74], antileukotrienes 4.83 [1.63-14.34], theophylline: 2.46 [1.23-4.91], and oral corticosteroids: [2.99;.1.26-7.08]). No independent association was found with dyspnea, QoL, exacerbations, and mortality.
  
  
  CONCLUSIONS
  Compared to 'pure' COPD patients, patients with ACOS exhibit lower cumulative smoking, suffer more from obesity and atopic diseases, and use more asthma treatments. Disease severity (dyspnea, QoL, exacerbations, comorbidities) and prognosis (mortality) are not different from 'pure' COPD patients.
authors: Pulmonary Department, Gabriel Montpied University Hospital, Auvergne University, Clermont-Ferrand, France.
authors: D
authors: D
authors: Caillaud
authors: Pulmonary Department, APHM, INSERM U1077, CNRS UMR 7733 Aix Marseille Université, Marseille, France.
authors: P
authors: P
authors: Chanez
authors: Pulmonary Department, Larrey University Hospital, Toulouse, France.
authors: R
authors: R
authors: Escamilla
authors: Respiratory and Intensive Care Medicine, Cochin Hospital, AP-HP and Paris Descartes University, Sorbonne Paris Cité, Paris, France.
authors: P-R
authors: PR
authors: Burgel
authors: Pulmonary Department, University Hospital, Saint-Etienne, France.
authors: I
authors: I
authors: Court-Fortune
authors: Pulmonary Department, La Croix Rousse University Hospital, Lyon, France.
authors: P
authors: P
authors: Nesme-Meyer
authors: Pulmonary Department, Maison Blanche University Hospital, INSERM U903, Reims, France.
authors: G
authors: G
authors: Deslee
authors: Clinique des Maladies Respiratoires, Albert Calmette University Hospital, Lille, France.
authors: T
authors: T
authors: Perez
authors: EFFI-STAT, Paris, France.
authors: J-L
authors: JL
authors: Paillasseur
authors: Polyclinique Les Fleurs, Pneumologie, Ollioules, France.
authors: C
authors: C
authors: Pinet
authors: Pulmonary Department, Bichat Hospital, AP-HP, Paris, France.
authors: G
authors: G
authors: Jebrak
authors: Respiratory and Intensive Care Medicine, Cochin Hospital, AP-HP and Paris Descartes University, Sorbonne Paris Cité, Paris, France.
authors: N
authors: N
authors: Roche
mesh_terms: D000368:Aged; D001249:Asthma / Q000150:complications* / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005602:France; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology; D011788:Quality of Life; D012307:Risk Factors; D011795:Surveys and Questionnaires; D063189:Symptom Assessment; D013577:Syndrome
keywords: Asthma-COPD overlap syndrome (ACOS); asthma-COPD overlap syndrome; chronic obstructive pulmonary disease (COPD); mortality; severity; treatment