[Epidemiology of lower extremity artery disease]

It is estimated that more than 200 million individuals are affected by lower extremity artery disease (LEAD) worldwide. This prevalence has increased between 2000 and 2010 by 25%, especially in low/middle income countries. In France, about one million people are affected by this condition. Almost two-thirds of patients with LEAD are asymptomatic. This explains the interest of the measurement of the ankle-brachial index (ABI), an objective and harmless diagnostic tool. An ABI≤0.90 is considered as diagnostic for LEAD. The detection of symptomatic LEAD requires standardized questionnaires identifying intermittent claudication. Epidemiological studies on chronic limb-threatening ischemia (CLTI) - the most severe presentation of the disease - are scarce: the prevalence is estimated around 0.5-2.0% after the age of 40, mostly affecting elderly people. Similar to other atherosclerotic diseases, the risk factors are multiple (genetic factors, traditional risk factors, metabolic and inflammatory factors, socioeconomic factors), with different weighs of association as compared to coronary artery diseases. Due to their high prevalence and strength of association, cigarette smoking and hypertension are the most frequent purveyors of this disease in population. Diabetes mellitus is a strong risk factor, and its increasing prevalence contributes to the global epidemics of LEAD. In claudicants, the 5-year amputation risk is estimated at 5%, increasing to 25% at one year in case of CLTI. However, the main risk is related to general cardiovascular events. It is estimated that patients with LEAD present concomitantly coronary and cerebrovascular disease in respectively 50% and 20% of cases. The non-cardiovascular mortality, especially related to cancer, is also higher than in general population. Overall, the control of traditional risk factors has a beneficial effect both for the limb and general prognosis.