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Objectives To determine whether poor lower extremity nerve function is associated with less-favorable calf muscle characteristics and greater functional impairment in people with and without peripheral arterial disease ( PAD). Design Cross-sectional. Setting Three Chicago-area medical centers. Participants Four hundred thirteen participants with PAD (ankle-brachial index ( ABI) < 0.90) and 255 without. Measurements Electrodiagnostic testing of the peroneal nerve was performed. Calf muscle cross-sectional area and percentage fat were measured using computed tomography at 66.7% of the distance between the distal and proximal tibia. Six-minute walk performance was measured. Results Adjusting for age, sex, race, ABI, leg symptoms, smoking, physical activity, comorbidities, and other covariates, lower peroneal nerve conduction velocity ( NCV) was associated with lower calf muscle area (first quartile 4,770.3 mm2, fourth quartile 5,571 mm2, P < .001) and poorer 6-minute walk distance (first quartile 989.2 feet, fourth quartile 1,210.8 feet, P < .001) in participants without diabetes mellitus with PAD. Lower peroneal NCV was associated with lower calf muscle area (first quartile 5,166.0 mm2, fourth quartile 6,003.8 mm2, P = .01) and poorer 6-minute walk distance (first quartile 866.4 feet, fourth quartile 1,082.5 feet, P = .01) in participants with diabetes mellitus and PAD as well. In participants without PAD, lower peroneal NCV was not associated with lower calf muscle area but was associated with poorer 6-minute walk distance only in participants without diabetes mellitus (first quartile 1,317.0 feet, fourth quartile 1,570.4 feet, P-trend < .001). Conclusion Lower peroneal nerve function is associated with smaller calf muscle area and greater functional impairment in individuals with PAD. Future study is needed to determine whether improving peroneal NCV prevents loss of calf muscle and functional decline in people with PAD. [ABSTRACT FROM AUTHOR]

Background: The ankle brachial index (ABI) is a noninvasive, reliable measure of lower-extremity ischemia. However, the relationship between ABI and lower-extremity function has not been well studied. Objectaive: To describe the association between the ABI and lower-extremity function. Design: Cross-sectional study. Setting: 3 academic medical centers in the Chicago area. Participants: 740 men and women (460 with peripheral arterial disease). Measurements: Accelerometer-measured physical activity over 7 days, 6-minute walk, 4-m walking velocity, standing balance, and ABI. Results: 33% of participants with peripheral arterial disease had intermittent claudication. Fewer than 40% of participants with an ABI less than 0.40 walked continuously for 6 minutes compared with more than 95% of participants with an ABI between 1.00 and 1.50. Compared with an ABI of 1.10 to 1.50, an ABI less than 0.50 was associated with shorter distance walked in 6 minutes (β-regression coefficient = -523 ft [95% CI, -592 to -454 ft]; P < 0.001), less physical activity (β = -514.8 activity units [CI, -657 to -373 activity units]; P < 0.001), slower 4-m walking velocity (β = -0.21 m/s [CI, -0.27 to -0.15 m/s]; P < 0.001), and less likelihood of maintaining a tandem stand for 10 seconds (odds ratio, 0.37 [CI, 0.18 to 0.76]; P= 0.007), after adjustment for typical confounders. Associations between ABI and function were stronger than associations between leg symptoms and function. Conclusions: The ABI, a noninvasive test that can be performed in a medical office, is more closely associated with leg function in persons with peripheral arterial disease than is intermittent claudication or other leg symptoms. These data support the use of the ABI to identify abnormal lower-extremity function. [ABSTRACT FROM AUTHOR]