title: A Belgian survey on the diagnosis of asthma-COPD overlap syndrome.
abstract: BACKGROUND
  Patients with chronic airway disease may present features of both asthma and COPD, commonly referred to as asthma-COPD overlap syndrome (ACOS). Recommendations on their diagnosis are diffuse and inconsistent. This survey aimed to identify consensus on criteria for diagnosing ACOS.
  
  
  METHODS
  A Belgian expert panel developed a survey on ACOS diagnosis, which was completed by 87 pulmonologists. Answers chosen by ≥70% of survey respondents were considered as useful criteria for ACOS diagnosis. The two most frequently selected answers were considered as major criteria, others as minor criteria. The expert panel proposed a minimal requirement of two major criteria and one minor criterion for ACOS diagnosis. Respondents were also asked which criteria are important for considering inhaled corticosteroids prescription in a COPD patient.
  
  
  RESULTS
  To diagnose ACOS in COPD patients, major criteria were "high degree of variability in airway obstruction over time (change in forced expiratory volume in 1 second ≥400 mL)" and "high degree of response to bronchodilators (>200 mL and ≥12% predicted above baseline)". Minor criteria were "personal/family history of atopy and/or IgE sensitivity to ≥1 airborne allergen", "elevated blood/sputum eosinophil levels and/or increased fractional exhaled nitric oxide", "diagnosis of asthma <40 years of age"; "symptom variability", and "age (in favor of asthma)". To diagnose ACOS in asthma patients, major criteria were "persistence of airflow obstruction over time (forced expiratory volume in 1 second/forced vital capacity ratio <0.7)" and "exposure to noxious particles/gases, with ≥10 pack-years for (ex-)smokers"; minor criteria were "lack of response on acute bronchodilator test"; "reduced diffusion capacity"; "limited variability in airway obstruction"; "age >40 years"; "emphysema on chest computed tomography scan".
  
  
  CONCLUSIONS
  Specific criteria were identified that may guide physicians to a more uniform diagnostic approach for ACOS in COPD or asthma patients. These criteria are largely similar to those used to prescribe inhaled corticosteroids in COPD.
authors.affiliation: Department of Respiratory Diseases, CHU Liège, University of Liège, Liège.
authors.forename: Didier
authors.initials: D
authors.lastname: Cataldo
authors.affiliation: Department of Respiratory Diseases, CHU Liège, University of Liège, Liège.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Corhay
authors.affiliation: Department of Respiratory Medicine, Ghent University Hospital, Ghent.
authors.forename: Eric
authors.initials: E
authors.lastname: Derom
authors.affiliation: Department of Respiratory Diseases, CHU Liège, University of Liège, Liège.
authors.forename: Renaud
authors.initials: R
authors.lastname: Louis
authors.affiliation: Department of Respiratory Medicine, CHU - UCL - Namur, Université catholique de Louvain, Yvoir; Molecular Physiology Research Unit (URPhyM)-NARILIS, Laboratory of General Physiology, University of Namur, Namur.
authors.forename: Eric
authors.initials: E
authors.lastname: Marchand
authors.affiliation: Chest Department, Erasme University Hospital, Université Libre de Bruxelles, Brussels.
authors.forename: Alain
authors.initials: A
authors.lastname: Michils
authors.affiliation: Department of Respiratory Medicine, University Hospital Saint-Pierre, Université Libre de Bruxelles, Brussels.
authors.forename: Vincent
authors.initials: V
authors.lastname: Ninane
authors.affiliation: Department of Respiratory Medicine, University Hospital Vésale, Montigny-le-Tilleul.
authors.forename: Rudi
authors.initials: R
authors.lastname: Peché
authors.affiliation: Department of Respiratory Medicine, Cliniques universitaires St Luc, Université Catholique de Louvain, Brussels.
authors.forename: Charles
authors.initials: C
authors.lastname: Pilette
authors.affiliation: Respiratory Division, University Hospital Brussels (UZ Brussel), Vrije Universiteit Brussel, Brussels.
authors.forename: Walter
authors.initials: W
authors.lastname: Vincken
authors.affiliation: Department of Respiratory Diseases, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Janssens
mesh_terms: D000280:Administration, Inhalation; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D001530:Belgium / Q000453:epidemiology; D001993:Bronchodilator Agents / Q000008:administration & dosage; D032921:Consensus; D003661:Decision Support Techniques; D005260:Female; D005541:Forced Expiratory Volume; D006306:Health Surveys; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D000072106:Pulmonologists; D012129:Respiratory Function Tests; D011795:Surveys and Questionnaires; D013577:Syndrome; D014797:Vital Capacity
chemical_list: D001993:Bronchodilator Agents
keywords: ACOS; COPD; airway obstruction; asthma; diagnosis; inhaled corticosteroids