Association between meeting daily step count goals with ambulatory function and quality of life in patients with claudication

Abstract

Objective: To determine (a) whether patients with peripheral artery disease (PAD) who walked at least 7000 and 10,000 steps/day had better ambulatory function and health-related quality of life (HRQoL) than patients who walked less than 7000 steps/day, and (b) whether differences in ambulatory function and HRQoL in patients grouped according to these daily step count criteria persisted after adjusting for covariates.

Methods: Two hundred forty-eight patients were assessed on their daily ambulatory activity for 1 week with a step activity monitor, and were grouped according to daily step count targets. Patients who took fewer than 7000 steps/day were included in group 1 (n = 153), those who took 7000 to 9999 steps/day were included in group 2 (n = 57), and patients who took at least 10,000 steps/day were included in group 3 (n = 38). Primary outcomes were the 6-minute walk distance (6MWD) and Walking Impairment Questionnaire (WIQ) distance score, which is a disease-specific measurement of HRQoL. Patients were further characterized on demographic variables, comorbid conditions, and cardiovascular risk factors.

Results: The groups were significantly different on ankle-brachial index (P = .02), and on the prevalence of hypertension (P = .04), diabetes (P < .01), abdominal obesity (P < .01), arthritis (P = .04), and chronic obstructive pulmonary disease (P < .01). Thus, these variables served as covariates in adjusted analyses, along with age, weight, and sex. The 6MWD (mean ± standard deviation) was significantly different among the groups in unadjusted (P < .01) and adjusted (P < .01) analyses (group 1, 313 ± 90 m; group 2, 378 ± 84 m; and group 3, 414 ± 77 m), with groups 2 and 3 having a higher 6MWD than group 1 (P < .01). The WIQ distance score was significantly different among the groups in unadjusted (P < .01) and adjusted (P < .01) analyses (group 1, 30 ± 30%; group 2, 45 ± 35%; and group 3, 47 ± 34%), with groups 2 and 3 having higher WIQ distance scores than group 1 (P < .01).

Conclusions: Patients with PAD who walked more than 7000 and 10,000 steps/day had greater ambulatory function and HRQoL than patients who walked fewer than 7000 steps/day. Second, the greater ambulatory function and HRQoL associated with walking 7000 and 10,000 steps/day persisted after adjusting for covariates. This study provides preliminary evidence that patients with PAD who walk more than 7000 steps/day have better ambulatory function and HRQoL than patients below this threshold.

Keywords: 6-minute walk; Exercise; Intermittent claudication; Physical activity; Steps; Treadmill test.