Measurement of Walking Distance and Speed in Patients With Peripheral Arterial Disease

Abstract

Background-The maximal walking distance (MWD) performed on a treadmill test remains the "gold standard" in estimating the walking capacity of patients who have peripheral arterial disease with intermittent claudication, although treadmills are not accessible to most physicians. We hypothesized that global positioning system (GPS) recordings could monitor community-based outdoor walking and provide valid information on walking capacity in patients with peripheral arterial disease. Methods and Results-We studied 24 patients (6 women

The Treadmill Is a Better Functional Test Than the 6-Minute Walk Test in Therapeutic Trials of Patients With Peripheral Artery Disease

“…20,21,26,49 Maximal walking distance on a progressive treadmill protocol was also correlated with outdoor walking distance measured with a global positioning system. 50 These relationships between the graded treadmill and patientreported outcomes provide evidence that understanding peak PAD-limited exercise capacity is a relevant parameter in also understanding a patient's daily activities that are performed at work intensities well below the patient's peak capability. Thus, treadmill testing provides a facile laboratory measure reflecting patients' ambulatory status and function.…”

Letter by Le Faucheur et al Regarding Articles, “Six-Minute Walk Is a Better Outcome Measure Than Treadmill Walking Tests in Therapeutic Trials of Patients With Peripheral Artery Disease” and “The Treadmill Is a Better Functional Test Than the 6-Minute Walk Test in Therapeutic Trials of Patients With Peripheral Artery Disease”

“…Median GPS MWD was reported to be on average 4.1 times higher than MWD from TWT. 5 This is an average coefficient, but a wider discrepancy exists for some PAD patients, suggesting that TWT could importantly underestimate real-life outdoor walking capacity. From the same study, median GPS MWD was on average 2.2 times higher than the 6MWT total walked distance.…”

“…Community-based global positioning system (GPS) measurement has been recently proposed to assess outdoor walking capacity in PAD patients, that is, under conditions expected to be closer to real life. [3][4][5] Although an emerging approach, GPS assessment provides some interesting insights, adding arguments to the aforementioned controversies.…”

“…Considering that an optimal functional test should directly correlate with patient-reported physical limitations, a recent study showed that patient-reported measures of walking limitation tended to correlate better with a GPS assessment of the maximal walking distance (MWD) than they do with the 6MWT and a graded TWT. 3 Regarding the agreement between GPS assessment and both TWT and 6MWT, available studies reported that GPS maximal 5 or total 4 walking distance was correlated to both TWT (r=0.81, P<0.001) and 6MWT (r=0.78, P<0.001). Median GPS MWD was reported to be on average 4.1 times higher than MWD from TWT.…”

“…From the same study, median GPS MWD was on average 2.2 times higher than the 6MWT total walked distance. 5 Should we thus consider that the 6MWT is a better surrogate of reallife walking capacity? One main limitation of the 6MWT is that the test is limited to a relatively short total duration.…”