The natural history of claudication: risk to life and limb.

Although a patient with intermittent claudication (IC) will fear progression to severe disease and amputation, this is a relatively rare outcome of claudication, with only 1% to 3% of claudicants ever requiring major amputation over a 5-year period. Indeed, in one study, 50% of claudicants became symptom free during 5 years' follow-up. All the new evidence over the last 40 years has not altered the impression that only about one fourth of patients with IC will ever significantly deteriorate, and that deterioration is most frequent during the first year after diagnosis (6 to 9%) compared with 2% to 3% per annum thereafter. Smoking is the most important risk factor for the progression of local disease in the legs, with an amputation rate 11 times greater in smokers than nonsmokers. Diabetes, male gender, and hypertension are also important risk factors for progression. Because cerebrovascular disease (CVD), coronary artery disease (CAD), and peripheral arterial occlusive disease (PAOD) coexist, PAOD and IC should be regarded as a marker for increased risk from fatal and nonfatal cardiovascular event, and 2% to 4% of claudicants have a nonfatal cardiovascular event every year. The risk is higher in the first year after developing IC than in a long-standing stable claudicant, and the average claudicant is more likely to have a nonfatal myocardial infarction (MI) or stroke in the next year that of ever requiring a major amputation for his leg ischemia. The mortality in claudicants is 30% at 5 years, 50% at 10 years, and 70% at 15 years, without any clear decrease in these figures over the last 30 to 40 years. The mortality of claudicants is approximately two and a half times that of an age-matched general population.