The relation of peripheral arterial disease to leg force, gait speed, and functional dependence among older adults

Abstract

Background: Atherosclerotic peripheral arterial disease (PAD), common among older adults, is associated with poor low-extremity functioning. In considering functional status, varying domains exist, including activities of daily living (ADL), instrumental activities of daily living (IADL), low-extremity mobility (LEM), and leisure and/or social activities (LSA). However, little is known about how PAD is related to functional status beyond low-extremity functioning.

Methods: A total of 1798 participants 60 years old or older was selected from the population-based National Health and Nutrition Examination Survey 1999-2002 in the United States. ADL, IADL, LSA, LEM, and general physical activities (GPA) were obtained by self-report. Peak leg force was obtained from an isokinetic dynamometer. Habitual gait speed was obtained from a 20-foot timed walk. PAD was defined as an ankle-brachial blood pressure index <0.9 in either leg.

Results: After multivariable adjustment, the odds ratios (ORs) for dependence in IADL, LSA, and LEM comparing participants with PAD to those without were 1.60 (95% confidence interval [CI], 1.11-2.29), 1.63 (95% CI, 1.08-2.44), and 2.29 (95% CI, 1.64-3.18), respectively. Additional adjustment of peak leg force and/or habitual gait speed diminished the relations of PAD to dependence in IADL and LSA. PAD was associated with an 18.06 Newton reduction (p =.003) in peak leg force and a 0.05 m/s reduction (p =.002) in habitual gait speed.

Conclusion: PAD was independently associated with multiple domains of functional dependence. The association between PAD and dependence in IADL and LSA was to a large extent mediated by leg force and gait speed.