Free-living physical activity as a novel outcome measure in patients with intermittent claudication

Objective: To develop a method of event-based analysis that quantifies the fragmented nature of walking bouts in individuals with intermittent claudication [IC] and compare outcomes with age and gender-matched healthy controls. Design: Cross-sectional. Materials: The activPAL™ physical activity monitor. Methods: 7-day physical activity patterns were compared between individuals with IC (n = 30) and controls matched for age and gender (n = 30). The ratio of the number of walking events to upright events was calculated to provide an event-based claudication index (EBCI) that represented the fragmented nature of walking bouts commonly reported in those with IC. Results: Individuals with IC had a greater EBCI than age matched controls indicating a more fragmented walking pattern (5.8 ± 2.0 vs. 7.7 ± 3.1, p < 0.01). The difference between groups was more pronounced when the EBCI was calculated from upright events that included >400 steps (23.4 ± 11.3 vs. 35.8 ± 14.2, p < 0.01). Conclusion: The classic fragmented stop/start walking pattern universally described by individuals with IC can be quantified using the EBCI. This method of measurement potentially provides a novel method of assessing the effectiveness of clinical interventions for this patient group.