TY - JOUR T1 - The minimum important difference (MID) of the incremental shuttle walk (ISW) in COPD: Does baseline ISW influence estimates? JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - 414 AU - Claire M. Nolan AU - Jane L. Canavan AU - Samantha S.C. Kon AU - Sarah E. Jones AU - Michael I. Polkey AU - William D.-C. Man Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/414.abstract N2 - Background: The incremental shuttle walk (ISW) is a well-validated measure of exercise capacity in chronic obstructive pulmonary disease (COPD). Using a single anchor-based approach, the minimum important difference (MID) has previously been estimated at 47.5metres (m). However it is not known whether this applies also to those with low baseline exercise capacity. The aim of the study was to provide estimates of the MID for the ISW in patients with low baseline ISW.Methods: Inclusion criteria included a diagnosis of COPD, referred for pulmonary rehabilitation (PR) and a baseline ISW ≤100m. 197 patients (Mean (SD) age: 71 (10) years; FEV1 45 (21)%predicted; MRC dyspnoea 4.2 (0.8); Chronic Respiratory Disease Questionnaire (CRQ) total 66 (22); ISW 57.5 (27.8)m; 4-metre gait speed (4MGS): 0.65 (0.17) m/s) completed an 8-week outpatient PR programme. Using external anchors, receiver operating characteristic (ROC) curves and linear regression were used to provide anchor-based estimates of the MID.Results: Mean (95% CI) improvement in ISW with PR was 49 (41 to 57)m. Change in ISW correlated significantly with change in CRQ (domains and total) and change in 4MGS, but only the relationship with 4MGS had a r>0.3 (r=0.36; p<0.0001). Using linear regression and a change in 4MGS of 0.1m/s (known MID of the 4MGS) as the external anchor, estimate of the MID for the ISW ranged from 34.8 to 73.4m. Using ROC curves, the most reliable estimate of the MID at the individual level was 40m (AUC 0.70; p<0.001)Conclusion: The most reliable estimate of the MID of the ISW in patients with COPD with low baseline ISW is 40m and corroborates findings in unselected patients. ER -