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

TY - JOUR

T1 - The minimal important difference of the King's Brief Interstitial Lung Disease Questionnaire (K-BILD) and forced vital capacity in interstitial lung disease

AU - Patel, Amit

AU - Siegert, Richard

AU - Keir, Gregory J

AU - Bajwah, Sabrina

AU - Barker, Richard D

AU - Maher, Toby M

AU - Renzoni, Elisabetta A

AU - Wells, Athol U

AU - Higginson, Irene J

AU - Birring, Surinder

PY - 2013/9

Y1 - 2013/9

N2 - 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.

AB - 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.

U2 - 10.1016/j.rmed.2013.06.009

DO - 10.1016/j.rmed.2013.06.009

M3 - Article

C2 - 23867809

SN - 0954-6111

VL - 107

SP - 1438

EP - 1443

JO - Respiratory Medicine

JF - Respiratory Medicine

IS - 9

ER -