Lower Extremity Nerve Function, Calf Skeletal Muscle Characteristics, and Functional Performance in Peripheral Arterial Disease

Abstract

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.