Relationship between the Ankle-Brachial Index and the Risk of Coronary Heart Disease and Stroke: The Circulatory Risk in Communities Study

Abstract

AIM: Patients with peripheral artery disease (PAD) are at a high risk of cardiovascular disease (CVD) among Western populations. However, evidence for an elevated risk in Asian populations is limited. METHODS: This prospective cohort study examined 939 Japanese men 60-74 years of age at the time of the baseline survey. A total of 115 cases of CVD were detected during a median 9.3 years of follow-up, and the ankle brachial blood pressure index (ABI) functioned as a surrogate measurement of PAD. RESULTS: The age-adjusted risks of coronary heart disease, ischemic stroke and ischemic CVD (coronary heart disease and ischemic stroke) were higher among men in the lowest ABI tertile compared with that observed in the men in the highest tertile (<1.08 vs. >1.17). These associations did not change substantially after adjusting for cardiovascular risk factors. The respective multivariable hazard ratios (HRs, 95% CI) for the three conditions were as follows: 2.48 (1.08-5.71), p for trend=0.03; 1.95 (0.94-4.02), p for trend=0.04; and 2.16 (1.25-3.72), p for trend=0.004. These results did not vary based on a comparison of the three ABI categories: ≤0.90, 0.91-1.10 and >1.10. The multivariable HRs (95% CI) for an ABI ≤0.90 versus >1.10 were as follows: 2.04 (0.67-6.20), p for trend=0.14 for coronary heart disease; 3.39 (1.10-10.5), p for trend=0.006 for ischemic stroke; and 2.61 (1.19-5.76), p for trend=0.003 for ischemic CVD. There were no associations between the ABI and the risk of hemorrhagic stroke. CONCLUSIONS: A low ABI is associated with the risk of coronary heart disease, ischemic stroke and ischemic CVD in elderly Japanese men.