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

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.