The incremental shuttle walk test (ISW) in patients with bronchiectasis: Response to pulmonary rehabilitation (PR) and minimum clinically important difference (MCID)

Introduction: The ISW is a commonly used measure of exercise capacity in COPD, but little data exist in bronchiectasis. Lee et al. provided the first MCID estimate in a small cohort of 37 patients. However, the cohort was younger, had a higher ISW and were less breathlessness than those typically referred for PR. Aim: To determine the responsiveness of ISW to PR and provide estimates of the MCID in 119 patients with bronchiectasis. Method: The following outcome measures were collected before and after an 8-week PR programme: Medical Research Council (MRC) dyspnoea scale, ISW, Hospital Anxiety and Depression Score (HADS) and Chronic Respiratory Questionnaire (CRQ). Following PR, patients rated their response on a 5-point Global Rating of Change Questionnaire (GRCQ). Pre-to-post PR changes and effect size were calculated. Anchor-based methods were used to estimate the MCID of the ISW. Results: The baseline characteristics and response to PR are presented in Table 1 with ISW showing an effect size of 0.53. After PR, 95% of patients reported feeling ‘much’ or a ‘little better’ in response to the GRCQ. Using six different anchor-based estimates, the mean MCID of ISW was 58m. Conclusion: The ISW is responsive to PR in patients with bronchiectasis, with an MCID of 58m.