The Association between Ankle-Brachial Index and Cardiovascular or All-Cause Mortality in Metabolic Syndrome of Elderly Chinese

The ankle-brachial index (ABI) is a non-invasive, reliable measurement of lower-extremity ischemia. A low ABI is associated with increased risk of coronary heart disease, stroke and death. However, the relationship between ABI and all-cause mortality or cardiovascular disease (CVD) mortality in patients with metabolic syndrome (MetS) has not been well studied. Accordingly, we here investigated the association between ABI and all-cause and CVD mortality in an elderly Chinese population with MetS. A total of 2,274 MetS patients diagnosed under the criteria proposed by the International Diabetes Federation were divided into two groups based on repeated ABI measurement over a period of 13.6 months: ABI≤0.9 (n=525) and ABI 0.91–1.4 (n=1,749). Each of the baseline characteristics of age, systolic blood pressure, diabetes mellitus morbidity, and smoking history were significantly different between the two groups (p<0.05 or p<0.01). All-cause mortality and CVD mortality decreased gradually as the ABI increased from 0.4 to 1.4. In Cox regression analysis, the relative ratio of all-cause mortality to CVD mortality also showed a tendency to decrease with increasing ABI. In elderly patients with MetS, ABI is one of the most important indexes for determining the possible prognosis and predicting all-cause and CVD mortality. People with relatively older age, higher systolic blood pressure, diabetes mellitus morbidity and smoking history may be at risk of lower ABI (≤0.9) and higher all-cause and CVD mortality. Our results suggest the urgent need for repeated ABI measurement in clinical practice, both during individual visits and also over time, before diagnosing peripheral artery disease and making a therapeutic decision, especially in certain high-risk populations such as patients with MetS.