Abstract 3025: Association Of Systemic Insulin Sensitivity With Walking Distance In Peripheral Artery Disease

Abstract

Background: Skeletal muscle in patients with peripheral artery disease (PAD) is subjected to chronic ischemia and is known to be insulin resistant. The association of insulin resistance with walking distance in unclear. Research Question: Does systemic insulin sensitivity (assessed by Homeostatic Model Assessment of Insulin Resistance [HOMA-IR] and Adipose tissue insulin resistance index [Adipo-IR]) associate with 6-minute walk test distance (6MWT)? Aims: To understand the role insulin resistance plays in ambulatory impairment in PAD. Methods: Patients with PAD (defined as ABI <0.85) and age-matched controls (ABI 1.00-1.40) were recruited and underwent measurements of fasting glucose, free fatty acids (FFA), and insulin followed by 6-minute walk testing. HOMA-IR was calculated as (glucose [mg/dL] x insulin [uU/mL])/405 and Adipo-IR was calculated as FFA (mmol/L) x insulin (uU/mL). Comparisons between controls and those with PAD were done with Mann-Whitney U tests. Linear regression modeling was used to assess the association of insulin sensitivity with 6MWT. Results: Seventy subjects (median [IQR] age 67.5 [61.0, 73.0] years, 45 (64.3%) males) were recruited, including 20 controls and 50 with PAD. Insulin levels were significantly high in those with PAD (9.6 vs 12.1 uU/mL, p=0.05) while FFA (0.37 vs 0.34 mmol/L, p=0.04) levels were lower. Glucose levels were similar (77.9 vs 79.5 mg/dL, p=0.53). HOMA-IR was significantly higher in PAD (2.4 vs 2.0, p=0.03) while Adipo-IR was similar (3.9 vs 3.7, p=2.42). Insulin level, HOMA-IR, and Adipo-IR were significantly associated with 6MWT distance in univariate analysis, but no association was seen after adjusting for ABI, which strongly associated with walking distance. Conclusion: Patients with PAD exhibit systemic insulin resistance, although ABI was more strongly associated with 6MWT distance than the degree of insulin sensitivity.