The minimal important difference of the King's Brief Interstitial Lung Disease Questionnaire (K-BILD) and forced vital capacity in interstitial lung disease.

Health status and forced vital capacity (FVC) are widely used outcome measures of interstitial lung disease (ILD) but there is a paucity of studies reporting the minimal clinically meaningful change in these parameters. A study was undertaken to assess the minimal important difference (MID) of an ILD specific health status questionnaire, the King's Brief ILD questionnaire (K-BILD) and that of FVC in a range of ILDs. 57 patients with ILD (17 idiopathic pulmonary fibrosis; IPF) completed the K-BILD (score range 0-100) at 2 separate clinic visits. Patients underwent spirometry at both visits. The MID was determined by a range of distribution methods (Standard error of mean: SEM and 0.3× Effect size: ES) and anchor based methods (objective: FVC and subjective: global rating of change questionnaires, GRCQ). The MID was derived by calculating an average of all methods. Health status was reduced at baseline in all patients, mean (SD) K-BILD total score 62(23). The average MID for K-BILD total score incorporating all methods was an 8 unit change (range 6-10). The average MID for FVC was a 6% change of baseline (range 4-7%). The K-BILD is a responsive patient reported outcome measure for patients with ILD. It can potentially be used to assess patients in the clinic and evaluate the response to therapy. The MID of the K-BILD total score is 8 units. The MID for FVC for a range of ILDs was 6%, similar to that reported recently for patients with IPF. Our findings will facilitate the clinical interpretation of health status and FVC data in ILD.

Patel AS ，Siegert RJ ，Keir GJ ，Bajwah S ，Barker RD ，Maher TM ，Renzoni EA ，Wells AU ，Higginson IJ ，Birring SS ... -  《-》

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

Patel AS ，Siegert RJ ，Brignall K ，Gordon P ，Steer S ，Desai SR ，Maher TM ，Renzoni EA ，Wells AU ，Higginson IJ ，Birring SS ... -  《-》

The psychometric properties of the King's Brief Interstitial Lung Disease questionnaire and thresholds for meaningful treatment response in patients with progressive fibrosing interstitial lung diseases.

There is a lack of fully validated patient-reported outcome measures for progressive fibrosing interstitial lung disease (ILD). We aimed to validate the King's Brief Interstitial Lung Disease (K-BILD) questionnaire for measuring health-related quality of life (HRQoL) in these patients. We also aimed to estimate the meaningful change threshold for interpreting stabilisation of HRQoL as a clinical end-point in progressive fibrosing ILD, where the current goal of treatment is disease stability and slowing progression. This analysis evaluated data from 663 patients with progressive fibrosing ILD other than idiopathic pulmonary fibrosis from the INBUILD trial. Validation of the measurement properties was assessed for internal consistency, test-retest reliability, construct validity, known-groups validity and responsiveness. We calculated meaningful change thresholds for treatment response using anchor-based (within-patient) and distribution-based methods. K-BILD had strong internal consistency (Cronbach's α was 0.94 for total score, 0.88 for breathlessness and activities, 0.91 for psychological, and 0.79 for chest symptoms). The test-retest reliability intraclass correlation coefficient was 0.74 for K-BILD total score. K-BILD demonstrated weak correlations with forced vital capacity (FVC) percent predicted. Known-groups validity showed significant differences in K-BILD scores for patient groups with different disease severity based on use of supplemental oxygen or baseline FVC % pred (≤70% or >70%). We estimated a meaningful change threshold of ≥ -2 units for K-BILD total score for defining patients who remain stable/improved versus those with progressive deterioration. Our results validate K-BILD as a tool for assessing HRQoL in patients with progressive fibrosing ILD and set a meaningful change threshold of ≥ -2 units for K-BILD total score.

Birring SS ，Bushnell DM ，Baldwin M ，Mueller H ，Male N ，Rohr KB ，Inoue Y ... -  《-》

Translation and validation of the King's Brief Interstitial Lung Disease (K-BILD) questionnaire in French, Italian, Swedish, and Dutch.

Wapenaar M ，Patel AS ，Birring SS ，Domburg RTV ，Bakker EW ，Vindigni V ，Sköld CM ，Cottin V ，Vancheri C ，Wijsenbeek MS ... -  《-》

The King's Brief Interstitial Lung Disease (KBILD) questionnaire: an updated minimal clinically important difference.

Sinha A ，Patel AS ，Siegert RJ ，Bajwah S ，Maher TM ，Renzoni EA ，Wells AU ，Higginson IJ ，Birring SS ... -  《BMJ Open Respiratory Research》