Six-minute walk is a common outcome in clinical trials of people with lower extremity peripheral artery disease (PAD). However, meaningful change in six-minute walk distance is not well defined in people with PAD..
..777 participants with PAD (mean age: 71.2 years (standard deviation (SD)=8.8) mean baseline six-minute walk: 350.1 meters (SD=118.1) completed 5,439 questions about difficulty walking each WIQ distance at baseline and follow-up. Participants with PAD who reported no change in difficulty walking each WIQ distance between baseline and follow-up declined by 7.2 meters (95% CI: -11.6, -2.8) in the six-minute walk test. Relative to people reporting no change in difficulty walking, people reporting one and two point improvements in walking ability (0-4 scale) had six-minute walk distance improvements of 7.8 meters (95% CI:-0.3, +15.9) and 20.1 meters (95% CI: +1.1, +39.2), respectively. Relative to people reporting no change in walking difficulty, those reporting one and two point declines in perceived walking difficulty corresponded to -11.2 meter (-95% CI:-19.0, -3.4) and -23.8 meter (95% CI:-37.4, -10.3) declines in six-minute walk distance.
Among people with PAD, approximately 8 and 20 meter improvements in six-minute walk distance, respectively, represent small and large improvements in walking ability, respectively. People with PAD who reported no change in their ability to walk distances over one year simultaneously declined by a mean of seven meters in the six-minute walk test. These findings are useful for interpreting results of randomized trials of interventions to improve walking performance in people with PAD.