The relationship of walking distances estimated by the patient, on the corridor and on a treadmill, and the Walking Impairment Questionnaire in intermittent claudication

Physicians and patients consider the limited walking distance and perceived disability when they make decisions regarding (invasive) treatment of intermittent claudication (IC). We investigated the relationship between walking distances estimated by the patient, on the corridor and on a treadmill, and the Walking Impairment Questionnaire (WIQ) in patients with IC due to peripheral arterial disease. This was a single-center, prospective observational cohort study at a vascular laboratory in a university hospital in the Netherlands. The study consisted of 60 patients (41 male) with a median age of 64 years (range, 44-86 years) with IC and a walking distance ≤ 250 m on a standardized treadmill test. Main outcome measures were differences and Spearman rank correlations between pain-free walking distance, maximum walking distance (MWD) estimated by the patient, on the corridor and on a standardized treadmill test, and their correlation with the WIQ. The median patients' estimated, corridor, and treadmill MWD were 200, 200, and 123, respectively (P < .05). Although the median patients' estimated and corridor MWD were not significantly different, there was a difference on an individual basis. The correlation between the patients' estimated and corridor MWD was moderate (r = 0.61; 95% confidence interval [CI], 0.42-0.75). The correlation between patients' estimated and treadmill MWD was weak (r = 0.39; 95%, CI 0.15-0.58). Respective correlations for the pain-free walking distance were comparable. The patients' estimated MWD was moderately correlated with WIQ total score (r = 0.63; 95%, CI 0.45-0.76) and strongly correlated with WIQ distance score (r = 0.81; 95% CI, 0.69-0.88). The correlation between the corridor MWD and WIQ distance score was moderate (r = 0.59; 95% CI, 0.40-0.74). Patients' estimated walking distances and on a treadmill do not reflect walking distances in daily life. Instruments that take into account the perceived walking impairment, such as the WIQ, may help to better guide and evaluate treatment decisions