The minimal detectable difference for endurance shuttle walk test performance in people with COPD on completion of a program of high-intensity ground-based walking.
Study Goal
The researchers sought to determine the minimal detectable difference (MDD) in endurance shuttle walk test (ESWT) performance following supervised ground-based walking training in people with COPD.
Results Summary
The study found that the MDD for ESWT performance differed between anchor- and distribution-based approaches, and large variation in test performance suggests caution in using MDD to interpret individual changes.
Population
People with moderate-to-severe chronic obstructive pulmonary disease (COPD), aged 70 ± 8 years.
Effective Dosage
30-45 minutes, 2-3 times weekly.
Duration
8-10 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
supervised ground-based walking training | increase | endurance shuttle walk test (ESWT) performance | people with moderate-to-severe chronic obstructive pulmonary disease (COPD) | - | improved | #1 |
supervised ground-based walking training | increase | walking ability | participants with COPD | at least 'a little' better | perceived improvement | #2 |
BACKGROUND: In people with moderate-to-severe chronic obstructive pulmonary disease (COPD), the minimal detectable difference (MDD) in endurance shuttle walk test (ESWT) performance following exercise training is unclear. We sought to determine the MDD for ESWT performance following supervised ground-based walking training using anchor- and distribution-based approaches and report whether these values exceeded random variation in test performance. METHODS: Participants with COPD trained for 30-45 min, 2-3 times weekly for 8-10 weeks. The ESWT was performed before and after the training period. Immediately after training, participants rated their change in walking ability using a Global Rating of Change scale. Receiver Operating Characteristic curves were used to derive the value that best separated those who perceived their improvement in walking ability to be at least 'a little' better from 'almost the same, hardly any change'. These values were compared with those calculated using a distribution-based method. Random variation in test performance was defined as the minimal detectable change (MDC), calculated using the standard error of measurement. RESULTS: 78 participants (aged 70 ± 8 yr and FEV CONCLUSIONS: The MDD established using the anchor- and distribution-based approaches differed considerably. Large variation in test performance cautions against using the MDD to interpret changes in an individual. CLINICAL TRIALS REGISTRATION: Australian New Zealand Clinical Trials Registry (ACTRN12609000472279).