The Relation of Peripheral Arterial Disease to Leg Force, Gait Speed, and Functional Dependence Among Older Adults

Abstract

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. 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. 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. 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.