Minimal important difference for London Chest Activity of Daily Living scale in patients with chronic obstructive pulmonary disease

Abstract

ObjectivesTo determine the minimal important difference (MID) for the London Chest Activity of Daily Living scale (LCADL) in patients with chronic obstructive pulmonary disease (COPD), focusing on the percentage of the total score (LCADL%total), using an anchor-based method in addition to distribution-based methods. DesignNon-controlled before-and-after study. SettingTwo outpatient centres. ParticipantsSeventy-seven patients with COPD (GOLD II–IV, 47 males, forced expiratory volume in 1second mean 37 (SD 14) % predicted). InterventionsAerobic training and localised training for upper and lower limbs was conducted for 24 sessions, three times per week. Main outcome measuresThe main outcome was LCADL score pre- and post-exercise training. The MID was established using distribution and anchor-based methods. The modified Saint George Respiratory Questionnaire was the anchor for the analysis of sensitivity and specificity of the MID. ResultsThe established MIDs ranged from −2.1 to −5.9 points for LCADLtotal and from −2 to −6 points for LCADL%total. The receiver operating characteristic curve indicated a cut-off point of −3 points for LCADLtotal (sensitivity 51%, specificity 82%; P=0.01) and −4 points for LCADL%total (sensitivity 56%, specificity 82%; P=0.04). ConclusionsThe present findings suggest −3 points and −4 points as the MIDs for LCADLtotal and LCADL%total, respectively. Clinical trial registration numberClinicalTrials.gov NCT03251781.