Quality of Life Questionnaire-Bronchiectasis: Final psychometric analyses and determination of minimal important difference scores

Alexandra L. Quittner, Anne E. O'Donnell, Matthias A. Salathe, Sandra A. Lewis, Xiaoming Li, A. Bruce Montgomery, Thomas G. O'Riordan, Alan F. Barker

Research output: Contribution to journalArticle

64 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)12-20
Number of pages9
JournalThorax
Volume70
Issue number1
DOIs
StatePublished - Jan 1 2015

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

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    Quittner, A. L., O'Donnell, A. E., Salathe, M. A., Lewis, S. A., Li, X., Montgomery, A. B., O'Riordan, T. G., & Barker, A. F. (2015). Quality of Life Questionnaire-Bronchiectasis: Final psychometric analyses and determination of minimal important difference scores. Thorax, 70(1), 12-20. https://doi.org/10.1136/thoraxjnl-2014-205918