The development and validation of the King's Brief Interstitial Lung Disease (K-BILD) health status questionnaire

• Published in: Thorax Vol. 67; no. 9; pp. 804 - 810
• Main Authors: Patel, Amit S, Siegert, Richard J, Brignall, Katherine, Gordon, Patrick, Steer, Sophia, Desai, Sujal R, Maher, Toby M, Renzoni, Elisabetta A, Wells, Athol U, Higginson, Irene J, Birring, Surinder S
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Thoracic Society 01.09.2012; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: airway epithelium; allergic alveolitis; ANCA related vasculitides; asbestos-induced lung disease; Biological and medical sciences; bronchiectasis; Cardiology. Vascular system; Chi-Square Distribution; Clinics; connective tissue disease; COPD mechanisms; cough/mechanisms/pharmacology; cystic fibrosis; drug-induced lung disease; Female; Health Status; Hospitals; Humans; idiopathic pulmonary fibrosis; interstitial fibrosis; interstitial lung disease; London; Lung diseases; Lung Diseases, Interstitial - physiopathology; lung physiology; lung transplantation; Male; Medical imaging; Medical sciences; Mortality; Multivariate analysis; non-invasive ventilation; NSIP; Palliative care; Pneumology; Predictive Value of Tests; pulmonary eosinophilia; pulmonary vasculitis; Quality of life; Questionnaires; rare lung diseases; respiratory measurement; Respiratory system : syndromes and miscellaneous diseases; sarcoidosis; Severity of Illness Index; Studies; Surveys and Questionnaires; systemic disease and lungs; α1 antitrypsin deficiency; London; Validation; Lung disease; Questionnaire; Respiratory disease; Health; Development; Interstitial pneumonitis; Anesthesia; Circulatory system; Cardiology
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thoraxjnl-2012-201581

RationaleHealth status is impaired in patients with interstitial lung disease (ILD). There is a paucity of tools that assess health status in ILD. The objective of this study was to develop and validate the King's Brief Interstitial Lung Disease questionnaire (K-BILD), a new health status measure for patients with ILD.MethodsPatients with ILD were recruited from outpatient clinics. The development of the questionnaire consisted of three phases: item generation; item reduction, allocation to domains by factor analysis, Rasch analysis to create unidimensional scales and validation; and repeatability testing.Results173 patients with ILD (49 with idiopathic pulmonary fibrosis) completed a preliminary 71-item questionnaire. 56 items were removed due to redundancy, low factor loadings or poor fit to the Rasch model. The final version of the K-BILD questionnaire consisted of 15 items and three domains (breathlessness and activities, chest symptoms and psychological). Internal consistency assessed with Cronbach's α coefficient was 0.94 for the K-BILD total score. Concurrent validity of the K-BILD questionnaire was high compared with St George's Respiratory Questionnaire (r=0.90) and moderate with lung function (vital capacity, r=0.50). The K-BILD questionnaire was repeatable over 2 weeks (n=44), with intraclass correlation coefficients for domains and total score 0.86–0.94. The K-BILD construct validity for patients with idiopathic pulmonary fibrosis was similar to that of other ILDs.ConclusionThe K-BILD questionnaire is a brief, valid, self-completed health status measure for ILD. It could be used in the clinic to assess ILD from the patients' perspective.