Relationship between Ankle-Brachial Index and Chronic Kidney Disease in Hypertensive Patients with No Known Cardiovascular Disease

Both decreased GFR and albuminuria are associated with an elevated prevalence of peripheral artery disease. However, the combined effects of these alterations previously were not evaluated. Patients with hypertension and with no known vascular disease (n = 955; mean age 66 yr; 56% male) were selected from internal medicine outpatient clinics throughout Spain. Cardiovascular risk factors, urinary albumin excretion, and the ankle-brachial index (ABI) were assessed in all participants. GFR was estimated according to the Cockroft-Gault equation. Of the study population, 62% had diabetes, 23.8% had a GFR <60 ml/min per 1.73 m2, and 43.8% had albuminuria. The prevalence of ABI <0.9 was greater in patients with a GFR <60 ml/min per 1.73 m2 (37.4 versus 24.3%; P < 0.0001) and in those who had albuminuria (32.2 versus 23.3%; P = 0.001). In patients with both alterations, the prevalence of ABI <0.9 was 45.7%. Multivariate analysis indicated that the factors that were associated independently with low ABI were age (odds ratio [OR] 1.06; 95% confidence interval [CI] 1.03 to 1.08; P < 0.0001), triglyceride concentration (OR 1.003; 95% CI 1.001 to 1.005; P = 0.001), presence of albuminuria (OR 1.61; 95% CI 1.18 to 2.20; P = 0.003), smoking habit (OR 1.72; 95% CI 1.13 to 2.63; P = 0.012), and a GFR <60 ml/min per 1.73 m2 (OR 1.47; 95% CI 1.01 to 2.17; P = 0.049). In patients with hypertension and without known vascular disease, reduced GFR and albuminuria are associated independently with an ABI <0.9. Their combined presence characterizes a subgroup of the population who have an elevated prevalence of peripheral artery disease and could benefit from early diagnosis and treatment.