Systematic Review of Association Between Low Ankle–Brachial Index and All-Cause Cardiovascular, or Non-cardiovascular Mortality

The ankle–brachial index (ABI) is the ratio of the ankle versus brachial systolic blood pressure. ABI of <0.90 indicates the presence of peripheral arterial disease. Some studies indicated that ABI may correlate with the all-cause mortality. The aim of this study was to assess the prognostic significance of ABI of <0.90 as such predictor of all-cause mortality. In addition, we wished to test the association between ABI and cardiovascular or non-cardiovascular mortality. To this end, we carried out a systematic review of the studies published in MEDLINE that reported both ABI and all-cause mortality. The endpoint of interest was the all-cause mortality, including death from coronary disease, stroke, or other causes. Ten studies, with a total of 22,705 patients, were included in this review. ABI of <0.90 was proved to be associated with an increased risk of all-cause mortality [odds ratio 2.74 (95 % confidence interval 2.03–3.68) and number needed to harm 1.66], as well as with cardiovascular [i.e., death from coronary disease or stroke; respectively, 3.23 (1.98–5.29) and 1.26] and non-cardiovascular mortality [respectively, 2.23 (1.40–3.55) and 1.29]. In conclusion, ABI of <0.9 is useful as a prognostic factor for all-cause mortality.