Abnormally High Ankle-Brachial Index is Associated with All-cause and Cardiovascular Mortality: The REGICOR Study.

Abstract

The clinical significance of a high ankle brachial index (ABI) and its relationship to cardiovascular disease (CVD) and mortality is controversial. The aim of this study was to estimate the association between abnormally high ABI ≥ 1.4 and coronary heart disease (CHD), cerebrovascular disease, and all-cause mortality in a Mediterranean population without CVD. A prospective population based cohort study of 6352 subjects was followed up for a median 6.2 years. Subjects under 35 years, with a history of CVD or an ABI < 0.9 were excluded. All CHD events (angina, myocardial infarction, coronary revascularisation), cerebrovascular events (stroke, transient ischaemic attack), and all-cause mortality were recorded. A total of 5679 subjects fulfilled the inclusion criteria, of which 5517 (97.1%) had a normal ABI whereas 162 (2.9%) had an ABI ≥ 1.4. The profile of individuals with abnormally high ABI revealed as independent related factors age (OR = 1.0; p = .045), female sex (OR = 0.4; p < .01), diabetes (OR = 1.9; p = .02), and lower diastolic blood pressure (OR = 0.9; p < .001). During follow-up 309 (5.4%) participants presented with a CV event and 286 (5.0%) died. An ABI ≥ 1.4 was associated with a higher incidence of CV events in the univariate (HR = 1.7) but not in the multivariate survival Cox regression analysis. An ABI ≥ 1.4 was independently associated with all-cause mortality (HR = 2.0; IC 95% 1.32-2.92) and cardiovascular mortality (HR = 3.1; IC 95% 1.52-6.48). In subjects without CVD, those with abnormally high ABI do not have a greater CV event rate than those with a normal ABI. However, there seems to be a trend towards higher mortality risk, supporting the guidelines that consider this subgroup to be a high risk population.