title: Quality of Life Questionnaire-Bronchiectasis: final psychometric analyses and determination of minimal important difference scores.
abstract: BACKGROUND
  The Quality of Life-Bronchiectasis (QOL-B), a self-administered, patient-reported outcome measure assessing symptoms, functioning and health-related quality of life for patients with non-cystic fibrosis (CF) bronchiectasis, contains 37 items on 8 scales (Respiratory Symptoms, Physical, Role, Emotional and Social Functioning, Vitality, Health Perceptions and Treatment Burden).
  
  
  METHODS
  Psychometric analyses of QOL-B V.3.0 used data from two double-blind, multicentre, randomised, placebo-controlled, phase III trials of aztreonam for inhalation solution (AZLI) in 542 patients with non-CF bronchiectasis and Gram-negative endobronchial infection.
  
  
  RESULTS
  Excellent internal consistency (Cronbach's α ≥0.70) and 2-week test-retest reliability (intraclass correlation coefficients ≥0.72) were demonstrated for each scale. Convergent validity with 6 min walk test was observed for Physical and Role Functioning scores. No floor or ceiling effects (baseline scores of 0 or 100) were found for the Respiratory Symptoms scale (primary endpoint of trials). Baseline Respiratory Symptoms scores discriminated between patients based on baseline FEV₁% predicted in only one trial. The minimal important difference score for the Respiratory Symptoms scale was 8.0 points. AZLI did not show efficacy in the two phase III trials. QOL-B responsivity to treatment was assessed by examining changes from baseline QOL-B scores at study visits at which protocol-defined pulmonary exacerbations were reported. Mean Respiratory Symptoms scores decreased 14.0 and 14.2 points from baseline for placebo-treated and AZLI-treated patients with exacerbations, indicating that worsening respiratory symptoms were reflected in clinically meaningful changes in QOL-B scores.
  
  
  CONCLUSIONS
  Previously established content validity, reliability and responsivity of the QOL-B are confirmed by this final validation study. The QOL-B is available for use in clinical trials and routine clinical practice.
authors.affiliation: Department of Psychology & Pediatrics, University of Miami, and Behavioral Health Sciences Research, Coral Gables, Florida, USA.
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Quittner
authors.affiliation: Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, Georgetown University, Washington, District of Columbia, USA.
authors.forename: Anne E
authors.initials: AE
authors.lastname: O'Donnell
authors.affiliation: Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Miami, Miami, Florida, USA.
authors.forename: Matthias A
authors.initials: MA
authors.lastname: Salathe
authors.affiliation: Gilead Sciences Inc., Seattle, Washington, USA.
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Lewis
authors.affiliation: Gilead Sciences Inc., Seattle, Washington, USA.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Li
authors.affiliation: Cardeas Pharma Corp., Seattle, Washington, USA.
authors.forename: A Bruce
authors.initials: AB
authors.lastname: Montgomery
authors.affiliation: Gilead Sciences Inc., Seattle, Washington, USA.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: O'Riordan
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care, Oregon Health & Science University, Portland, Oregon, USA.
authors.forename: Alan F
authors.initials: AF
authors.lastname: Barker
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D001398:Aztreonam / Q000008:administration & dosage*; D001987:Bronchiectasis / Q000188:drug therapy / Q000503:physiopathology / Q000523:psychology*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life; D015203:Reproducibility of Results; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D001398:Aztreonam
keywords: Bronchiectasis; Perception of Asthma/Breathlessness; Respiratory Infection; Respiratory Measurement