Serum uric acid in hypertensive patients with and without peripheral arterial disease

Abstract

Background: Uric acid is frequently elevated in hypertension. In addition to renal and metabolic disturbances, lower limb ischemia might contribute to hyperuricemia among hypertensives complicated by peripheral arterial disease (PAD). Objective: To test the hypothesis that uric acid status is related to lower limb function in hypertensives with PAD. Methods: Serum and 24-h urine uric acid levels and other risk factors were examined in 145 hypertensives free of PAD and 166 hypertensives with PAD. Ankle/brachial index (ABI) and absolute claudication distance (in PAD) on a treadmill test (ACD) were assessed. Results: In multiple regression analysis for serum uric acid in the total group, PAD emerged as an independent determinant ( P=0.03) next to age ( P=0.005), triglycerides ( P=0.04), and insulin ( P=0.02). Serum uric acid concentrations were higher in hypertensives with PAD (404±101 vs. 347±80 μmol/l, P<0.001) independent of components of the metabolic syndrome (body mass index, triglycerides, insulin) and of age, gender, diabetes mellitus, pulse pressure, cholesterol, C-reactive protein, and treatment. After adjustment for kidney function by uric acid/creatinine ratio, values remained higher in hypertensives with PAD ( P=0.01). Uric acid excretion was higher in the PAD group ( P<0.001), whereas uric acid clearance was comparable between both groups. In multiple regression analysis for ACD (357±183 m) in the PAD group, serum uric acid ( P=0.02), C-reactive protein ( P<0.0001), age ( P=0.02), and smoking ( P=0.004) were independently associated. ABI (0.62±0.17) was not related to uric acid in PAD patients. Conclusion: Hyperuricemia is more pronounced in hypertensives complicated by PAD and is associated with worse functional status of the peripheral circulation.