Ankle-brachial blood pressure index predicts all-cause and cardiovascular mortality in hemodialysis patients

Abstract

A reduction in ankle-brachial BP index (ABPI) is associated with generalized atherosclerotic diseases and predicts cardiovascular mortality and morbidity in several patient populations. However, a large-scale analysis of ABPI is lacking for hemodialysis (HD) patients, and its use in this population is not fully validated. A cohort of 1010 Japanese patients undergoing chronic hemodialysis was studied between November 1999 and May 2002. Mean age at entry was 60.6 +/- 12.5 yr, and duration of follow-up was 22.3 +/- 5.6 mo. Patients were stratified into five groups (< 0.9, > or = 0.9 to < 1.0, > or = 1.0 to < 1.1, > or = 1.1 to < 1.3, and > or = 1.3) by ABPI measured at entry by an oscillometric method. The frequency distribution of ABPI was 16.5% of patients < 0.9, 8.6% of patients > or = 0.9 to < 1.0, 16.9% of patients 1.0 > or = to < 1.1, and 47.0% of patients > or 1.1 to < 1.3, whereas 10.9% of patients had an abnormally high ABPI (> or = 1.3). The relative risk of a history of diabetes mellitus (DM), cardiovascular, and cerebrovascular disease was significantly higher in patients with lower ABPI than those with ABPI > or = 1.1 to <1.3. During the study period, 77 cardiovascular and 41 noncardiovascular fatal events occurred. On the basis of Cox proportional hazards regression analysis, ABPI emerged as a strong independent predictor of all-cause and cardiovascular mortality. After adjustment for confounding variables, the hazard ratio (HR) for ABPI < 0.9 was 4.04 (95% confidence interval, 2.38 to 6.95) for all-cause mortality and 5.90 (2.83 to 12.29) for cardiovascular mortality. Even those with modest reductions in the ABPI (> or = 0.9 to <1.1) appeared to be at increased risk. Patients having abnormally high ABPI (> or = 1.3) also had poor prognosis (HR, 2.33 [1.11 to 4.89] and 3.04 [1.14 to 8.12] for all-cause and cardiovascular mortality, respectively). Thus, the present findings validate ABPI as a powerful and independent predictor for all-cause and cardiovascular mortality among hemodialysis patients.