title: The impact of dysfunctional breathing on the assessment of asthma control.
abstract: Dysfunctional breathing (DB) is a respiratory disorder, which involves a pattern of breathing too deeply, too superficially and/or too rapidly. In asthma patients, DB may lead to an overestimation of the severity of asthma symptoms, and hence potentially to overtreatment. However, it is not known to which degree DB may affect estimates of asthma control, in a specialist clinical setting.
  
  
  
  The MAPOut-study examined all patients referred consecutively over a 12-months period for specialist assessment of asthma at the Respiratory Outpatient Clinic at Bispebjerg Hospital in Copenhagen. All patients were examined with the Nijmegen questionnaire with a DB defined as a score ≥23 and the ACQ questionnaire. Linear regression analysis of predictors of ACQ score was performed. Asthma was defined as asthma symptoms and a positive asthma test.
  
  
  
  Of the 256 patients referred to the lung clinic, data on both the Nijmegen questionnaire and ACQ score was obtained in 127 patients, who were included in the present analysis. Median (range) age: 30 (15-63) years, and 76 (59.8%) were females. DB was found in 31 (24.4%). Asthmatic patients with co-existing DB had a poorer asthma control compared to asthmatics without DB (Median (range) ACQ score: 2.40 (0.20-4.60) vs 1.20 (0.00-4.40); p < 0.001.). A regression analysis showed that the effect of DB on asthma control was independent of airway hyperresponsiveness or airway inflammation in patients with DB.
  
  
  
  Dysfunctional breathing is common among asthma patients in a specialist setting, and results in a clinically significant underestimation of asthma control, which may potentially lead to overtreatment.
authors.affiliation: Respiratory Research Unit, Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark. Electronic address: sandravei@hotmail.com.
authors.forename: Sandra
authors.initials: S
authors.lastname: Veidal
authors.affiliation: Respiratory Research Unit, Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark.
authors.forename: Maria
authors.initials: M
authors.lastname: Jeppegaard
authors.affiliation: Respiratory Research Unit, Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark.
authors.forename: Asger
authors.initials: A
authors.lastname: Sverrild
authors.affiliation: Respiratory Research Unit, Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Backer
authors.affiliation: Respiratory Research Unit, Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark.
authors.forename: Celeste
authors.initials: C
authors.lastname: Porsbjerg
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology; D001985:Bronchial Provocation Tests / Q000379:methods; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D006985:Hyperventilation / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D013147:Spirometry / Q000379:methods; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014797:Vital Capacity / Q000502:physiology; D055815:Young Adult
chemical_list: D005938:Glucocorticoids
keywords: Asthma; Asthma control; Dysfunctional breathing; Nijmegen questionnaire