Association Between Daily Steps At Moderate Cadence And Vascular Outcomes In Patients With Claudication

Abstract

PURPOSES: We determined whether patients with peripheral artery disease and claudication grouped according to tertiles of community-based daily steps taken at a moderate cadence had differences in vascular function and biomarkers, and whether group differences in vascular function and biomarkers persisted after adjusting for demographic variables, comorbid conditions, and severity of PAD. METHODS: Two hundred sixty-three patients were assessed for one week on steps taken at a moderate cadence (exceeding 60 steps/min), and patients were placed into low (Group 1), intermediate (Group 2), and high (Group 3) tertiles. RESULTS: Ankle/brachial index (ABI) at 1 minute after exercise (mean ± SD) was significantly higher in Groups 2 and 3 than Group 1 in unadjusted (p < 0.01) and adjusted (p < 0.01) analyses (Group 1 = 0.34 ± 0.25, Group 2 = 0.38 ± 0.27, Group 3 = 0.44 ± 0.28). Exercise time to reach the minimum calf muscle oxygen saturation (StO2) value during treadmill exercise was significantly longer in Groups 2 and 3 than Group 1 in unadjusted (p < 0.01) and adjusted (p < 0.01) analyses (Group 1 = 127 ± 127 sec, Group 2 = 251 ± 266 sec, Group 3 = 310 ± 323 sec). Fibrinogen was significantly lower in Group 3 than Group 1 in unadjusted (p = 0.02) and adjusted (p = 0.05) analyses (Group 1 = 3.5 ± 1.2 g/L, Group 2 = 3.6 ± 1.5 g/L, Group 3 = 3.0 ± 1.1 g/L). CONCLUSIONS: Compared to patients with claudication in the lowest tertile of community-based daily steps taken at a moderate cadence, patients in the second and third tertiles had better calf muscle StO2 and ABI values during and immediately after exercise. Secondly, the most active group had lower fibrinogen levels than the least active group. This study provides preliminary evidence that a greater amount of community-based daily steps taken at a moderate cadence is positively associated with better vascular outcomes in patients with claudication. Supported by the NIA (R01-AG-24296) and GCRC (M01-RR-14467).