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

Objectives: To 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), using an anchor-based method in addition to distribution-based methods.

Design: Non-controlled before-and-after study.

Setting: Two outpatient centres.

Participants: Seventy-seven patients with COPD (GOLD II-IV, 47 males, forced expiratory volume in 1second mean 37 (SD 14) % predicted).

Interventions: Aerobic training and localised training for upper and lower limbs was conducted for 24 sessions, three times per week.

Main Outcome Measures: The 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.

Results: The established MIDs ranged from -2.1 to -5.9 points for LCADL and from -2 to -6 points for LCADL. The receiver operating characteristic curve indicated a cut-off point of -3 points for LCADL (sensitivity 51%, specificity 82%; P=0.01) and -4 points for LCADL (sensitivity 56%, specificity 82%; P=0.04).

Conclusions: The present findings suggest -3 points and -4 points as the MIDs for LCADL and LCADL, respectively.

Clinical Trial Registration Number: ClinicalTrials.gov NCT03251781.