title: Overlap syndrome--Asthma and obstructive sleep apnea.
abstract: BACKGROUND
  Asthma is a chronic inflammatory disease with multiple phenotypes. There is still a major gap in the understanding of its complex causality. Obstructive sleep apnea (OSA) is a common condition that has been implicated as a risk factor for asthma exacerbations.
  
  
  OBJECTIVE
  This study aims to characterize patients with the diagnosis of asthma and suspected OSA; identify the presence of OSA and review, on the current literature, the association between asthma and OSA, as an overlap syndrome.
  
  
  METHODS
  The authors present a retrospective study that included patients diagnosed with asthma that underwent sleep study in a 3 year period. Demographic, clinical data, body mass index (BMI), sleep study parameters and treatments were analyzed.
  
  
  RESULTS
  The sample consisted of 47 patients. The majority of population was females (68%) and the mean age was 55.65 ± 13.04 years. The most common nighttime symptom was snoring (93.6%). Regarding BMI, values above the normal limit were observed in 89.36% of the patients. 68% underwent polysomnography and the others cardiorespiratory polygraphy. In 57.4% of the patients, OSA was confirmed with a higher prevalence in males (73.3%) compared to females (50%). The therapeutic approach in 81.8% of these patients was home ventilation therapy.
  
  
  CONCLUSIONS
  The combination of asthma and OSA has become increasingly more frequent. In the described study, the prevalence of OSA was 57.4%, value that is in fact higher than in general population. After the therapeutic approach, all patients referred improvement of symptoms. It is therefore essential that OSA is investigated in patients with asthma when there is poor control of symptoms, in order to achieve a better control.
authors.affiliation: Pulmonology Department, Coimbra Hospital and University Centre, Portugal. Electronic address: madama.daniela@gmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Madama
authors.affiliation: Pulmonology Department, Coimbra Hospital and University Centre, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Silva
authors.affiliation: Pulmonology Department, Coimbra Hospital and University Centre, Portugal.
authors.forename: M J
authors.initials: MJ
authors.lastname: Matos
mesh_terms: D001249:Asthma / Q000150:complications / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis; D013577:Syndrome
keywords: Asthma; Obstructive sleep apnea; Overlap syndrome