title: Assessment of dyspnea in asthma: validation of The Dyspnea-12.
abstract: BACKGROUND
  Dyspnea is a prominent symptom in asthma. The Dyspnea-12 (D-12), an instrument that quantifies breathlessness using 12 descriptors that tap the physical and affective aspects, has shown promise for the measurement of dyspnea in cardiorespiratory disease.
  
  
  OBJECTIVE
  We report the results of a study designed to test the validity and reliability of the D-12 in a population of patients with asthma.
  
  
  METHODS
  This cross-sectional study included 102 patients with asthma. Subjects completed the D-12, Hospital Anxiety and Depression scale, St. George's Respiratory Questionnaire (SGRQ), and Medical Research Council scale. Confirmatory factor analysis confirmed the two-component structure of the D-12 (i.e., seven items that tap the physical aspects of breathlessness and five items that tap the affective aspects).
  
  
  RESULTS
  The D-12 subscales had excellent internal reliability (Cronbach's alpha for the "physical" score was 0.94 and the affective score was 0.95). The D-12 physical component was more strongly correlated with SGRQ Symptoms (r = 0.648), SGRQ Activities (r = 0.635) and Medical Research Council grade (r = 0.636), while the affective component was more strongly correlated with SGRQ Impacts (r = 0.765) and Hospital Anxiety and Depression scale scores (anxiety r = 0.641 and depression r = 0.602).
  
  
  CONCLUSIONS
  This study supports validity of the D-12 for use in the assessment of dyspnea of patients with asthma. It assesses one of the most pertinent symptoms of asthma from two viewpoints-physical and affective.
authors.affiliation: School of Nursing and Midwifery, College of Health & Social Care, University of Salford, Greater Manchester, UK. j.yorke@salford.ac.uk
authors.forename: Janelle
authors.initials: J
authors.lastname: Yorke
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Russell
authors.forename: Jeff
authors.initials: J
authors.lastname: Swigris
authors.forename: Caroline
authors.initials: C
authors.lastname: Shuldham
authors.forename: Carol
authors.initials: C
authors.lastname: Haigh
authors.forename: Nikki
authors.initials: N
authors.lastname: Rochnia
authors.forename: Jennifer
authors.initials: J
authors.lastname: Hoyle
authors.forename: Paul W
authors.initials: PW
authors.lastname: Jones
mesh_terms: D000328:Adult; D001249:Asthma / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D004417:Dyspnea / Q000175:diagnosis* / Q000209:etiology; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014797:Vital Capacity / Q000502:physiology; D016138:Walking / Q000502:physiology