title: Asthma-chronic obstructive pulmonary disease overlap syndrome - Literature review and contributions towards a Portuguese consensus.
abstract: BACKGROUND
  Phenotypic overlap between the two main chronic airway pulmonary diseases, asthma and chronic obstructive pulmonary disease (COPD), has been the subject of debate for decades, and recently the nomenclature of asthma-COPD overlap syndrome (ACOS) was adopted for this condition. The definition of this entity in the literature is, however, very heterogeneous, it is therefore important to define how it applies to Portugal.
  
  
  METHODS
  A literature review of ACOS was made in a first phase resulting in the drawing up of a document that was later submitted for discussion among a panel of chronic lung diseases experts, resulting in reflexions about diagnosis, treatment and clinical guidance for ACOS patients.
  
  
  RESULTS
  There was a consensus among the experts that the diagnosis of ACOS should be considered in the concomitant presence of: clinical manifestations characteristic of both asthma and COPD, persistent airway obstruction (post-bronchodilator FEV1/FVC<0.7), positive response to bronchodilator test (increase in FEV1of ≥200mL and ≥12% from baseline) and current or past history of smoking or biomass exposure. In reaching diagnosis, the presence of peripheral eosinophilia (>300eosinophils/μL or >5% of leukocytes) and previous history of atopy should also be considered. The recommended first line pharmacological treatment in these patients is the ICS/LABA association; if symptomatic control is not achieved or in case of clinical severity, triple therapy with ICS/LABA/LAMA may be used. An effective control of the exposure to risk factors, vaccination, respiratory rehabilitation and treatment of comorbidities is also important.
  
  
  CONCLUSIONS
  The creation of initial guidelines on ACOS, which can be applied in the Portuguese context, has an important role in the generation of a broad nationwide consensus. This will give, in the near future, a far better clinical, functional and epidemiological characterization of ACOS patients, with the ultimate goal of achieving better therapeutic guidance.
authors.affiliation: Institute of Health Sciences, Universidade Católica Portuguesa, Portugal; Pulmonology Department, Centro Hospitalar de São João, Porto, Portugal.
authors.forename: D
authors.initials: D
authors.lastname: Araújo
authors.affiliation: Institute of Health Sciences, Universidade Católica Portuguesa, Portugal; Pulmonology Department, Centro Hospitalar de São João, Porto, Portugal. Electronic address: eva.padrao@gmail.com.
authors.forename: E
authors.initials: E
authors.lastname: Padrão
authors.affiliation: Coordinator of Allergy Center of CUF Hospitals, Lisbon, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Morais-Almeida
authors.affiliation: Pulmonology Department, Centro Hospitalar de Lisboa Central, Lisboa, Portugal; Nova Medical School, Lisbon, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Cardoso
authors.affiliation: Institute of Health Sciences, Universidade Católica Portuguesa, Portugal.
authors.forename: F
authors.initials: F
authors.lastname: Pavão
authors.affiliation: Institute of Health Sciences, Universidade Católica Portuguesa, Portugal; Faculty of Health, Medicine and Life Sciences, Maastricht University, Portugal.
authors.forename: R B
authors.initials: RB
authors.lastname: Leite
authors.affiliation: Institute of Health Sciences, Universidade Católica Portuguesa, Portugal.
authors.forename: A C
authors.initials: AC
authors.lastname: Caldas
authors.affiliation: Pulmonology Department, Centro Hospitalar de São João, Porto, Portugal; Faculty of Medicine, University of Porto, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Marques
mesh_terms: D001249:Asthma / Q000150:complications / Q000175:diagnosis*; D032921:Consensus; D006801:Humans; D011174:Portugal; D017410:Practice Guidelines as Topic; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis*; D013577:Syndrome
keywords: Asthma; Chronic obstructive pulmonary disease; Overlap syndrome; Portuguese consensus