The minimal important difference in treadmill endurance test in COPD patients after a comprehensive pulmonary rehabilitation program (PRP)

Backgroud: As treadmill exercise testing is more representative of daily activity, our aim was to determine the minimal important difference (MID) for treadmill endurance test (TET) capable to detect improvement in functional capacity in patients with COPD after a a 24 sessions PRP. Material and methods: 100 COPD patients (mean age: 66.6±9.5 years old; FEV1: 44.8±20% pred) were enrolled. Patients performed a 6MWT and a symptom-limited TET at 90% of maximum grade achieved in an incremental test before and after the PRP. The St Georges Respiratory Questionnaire served as anchors for anchor-based MID estimates. Work rate (W), walked distance, endurance time and patients velocity in both tests were calculated. Results: The TET minimal important difference found for W was 14,337 Joules or 37% increase and for endurance time an increase of 340 s or 77%. View this table: Table 1. Changes and minimal important difference (MID) in 6 minute walk test (6MWT) and treadmill endurance test (TET), pre and post pulmonary rehabilitation program Conclusion: Treadmill endurance test is more representative of changes in functional capacity than 6MWT in COPD patients after a PRP. In addition, work rate seemed to be a good variable to evaluate improvement in exercise capacity after a pulmonary rehabilitation program.