The demographics of claudication and the aging of the American population.

Most peripheral artery disease is of ischemic atherosclerotic etiology and manifested as intermittent claudication (IC). Death and disability from atherosclerotic cardiovascular disease (CVD) is a growing problem because of the rapidly increasing elderly segment of the population. By the year 2015 the elderly will constitute 14.8% of Americans. Of the total 255 million, 13.8 million are over age 75 years and 9 million are women. On reaching age 65 years, the average remaining lifetime is 17.4 years. In the USA this 11% of the population accounts for 29% of the health costs and 70% of all deaths are attributable to cardiovascular disease. About 9.6% of cardiovascular events are due to peripheral artery disease manifested as IC requiring 777,000 office visits and 63,000 hospitalizations. Also, 17,400 deaths each year are attributed directly to this cause. The biennial incidence of IC in the Framingham Study was 7.1 per 1000 for men and 3.6% for women, increasing with age in both sexes up to age 75 years. At all ages there is a distinct male predominance. In the 35-64-year age range IC incidence is virtually identical to that of cardiac failure and stroke, but only one-third of CHD incidence. Beyond age 65 years IC incidence is only half that of other atherosclerotic cardiovascular conditions. The incidence of carotid bruits and non-palpable pedal pulses is virtually identical in the two sexes; only femoral bruits are male predominant. At time of diagnosis of IC one in three already have overt evidence of CHD, stroke or congestive heart failure (CHF). In those free of these at outset CHD and strokes occur at two to three times the general population rate and CHF 3.5-4.5 times the rate of persons without IC. Within 10 years of IC onset 43% develop CHD, 21% strokes and 24% cardiac failure. Carotid and femoral bruits are likewise harbingers of other atherosclerotic CVD. As many as 45% of IC victims lose their symptoms for extended periods. Survival following onset of IC is only two-thirds of that general population; after 10 years 60% died. This high mortality is largely attributable to coexistent cardiovascular impairments. A risk profile comprising the major cardiovascular risk factors predicts occurrence of IC even better than CHD. IC risk increases progressively with burden of the risk factors. With an aging population of increased size peripheral artery disease is a problem of increasing dimensions. Attention to comorbid conditions is essential if survival is to be improved. Because IC shares many of the same risk factors, measures to prevent CHD, CHF and strokes should also reduce IC risk.