Peripheral arterial disease prevalence
A study from the NHANES 1999–2000 data found that PAD affects approximately 5 million adults. Prevalence increases dramatically with age and disproportionately affects blacks. 2 However, the measurement of systolic blood pressure utilizing the right arm only and the omission of queries for surgical procedures to correct PAD in this study led to an underestimate of the true PAD prevalence. Experts in the field generally agree that PAD affects approximately 8 million Americans. 3
PAD affects 12-20 percent of Americans age 65 and older. Despite its prevalence and cardiovascular risk implications, only 25 percent of PAD patients are undergoing treatment. 4
In the general population, only about 10 percent of persons with PAD have the classic symptoms of intermittent claudication (IC). About 40 percent do not complain of leg pain, while the remaining 50 percent have a variety of leg symptoms different from classic claudication. 5 However, in an older, disabled population of women, as many as two-thirds of individuals with PAD had no exertional leg symptoms. 6
Persons with PAD have impaired function and quality of life. This is true even for persons who do not report leg symptoms.8
PAD is a marker for systemic atherosclerotic disease. Persons with PAD, compared to those without, have four-to-five times the risk of dying of a cardiovascular disease event, resulting in two-to-three times higher total mortality risk.9
In the Framingham Heart Study (FHS), the incidence of PAD was based on symptoms of intermittent claudication (IC) in subjects ages 29-62. Annual incidence of IC per 10,000 subjects at risk rose from six in men and three in women ages 30-44 to 61 in men and 54 in women ages 65-74. 10 IC incidence has declined since 1950, but mortality has remained high and unchanged. 11
Several studies have evaluated both symptomatic and asymptomatic PAD using the ankle-brachial index (ABI). The prevalence of asymptomatic PAD was 25.5 percent among 1,537 participants of the Systolic Hypertension in the Elderly Program (SHEP). 12
In the FHS, the annual mortality rate was almost four times greater in subjects with IC. In a major cohort study, investigators observed a 3.1-times higher risk for all-cause mortality compared with patients without PAD. In addition, PAD patients had a 5.9-times higher risk for death from cardiovascular disease complications and a 6.6-times higher risk for death from coronary heart disease specifically.13
African-American ethnicity was a strong and independent risk factor for PAD, and was not explained by higher levels of diabetes, hypertension, and BMI. African-Americans had a higher PAD prevalence than non-Hispanic whites (OR= 2.3). There was no evidence of a greater susceptibility of African-Americans to cardiovascular disease risk factors as a reason for their higher PAD prevalence.14
Data from NHANES, 1999–2000 (CDC/NCHS), show that even low blood levels of lead and cadmium may increase the risk of PAD. Exposure to these two metals is possible through cigarette smoke. The risk was 2.8 for high levels of cadmium and 2.9 for high levels of lead. The odds ratio of PAD for current smokers was 4.13 compared to people who had never smoked. 15
Results from the NHANES 1999-2000 survey of the CDC/NCHS showed a remarkable high prevalence of PAD among patients with renal insufficiency. Accurate identification of patients with renal insufficiency combined with routine ABI measurement in this group would greatly enhance efforts to detect subclinical PAD. 16
1(Hirsch AT, et al. Peripheral arterial disease detection, awareness and treatment in primary care. JAMA 2001; 286:1317-24; Criqui MH, et al. Mortality over a period of 10 years in patients with Peripheral arterial disease. NEJM 1992;326:381-6)
3 (Hirsch AT, et al. Peripheral arterial disease, detection, awareness, and treatment in primary care. JAMA 2001;286:1317–24; Criqui MH, et al. Mortality over a period of 10 years in patients with Peripheral arterial disease. NEJM 1992;326:381–6).
5 (Hirsch AT, et al. Peripheral arterial disease, detection, awareness, and treatment in primary care. JAMA 2001;286:1317-24; Criqui MH, et al. The sensitivity, specificity and predictive value of traditional clinical evaluation of Peripheral arterial disease: results from noninvasive testing in a defined population. Circulation 1985;71:516-22)
6 (Circulation 2001;104:504)
8 (McDermott MM, et al. The ankle brachial index is associated with leg function and physicial activity: the Walking and Leg Circulation Study. Ann Intern Med 2002;136:873–83); McDermott MM, et al. Functional decline in Peripheral arterial disease: associations with the ankle brachial index and leg symptoms. JAMA 2004;292:453–61)
9 (Criqui MH, et al. Mortality over a period of 10 years in patients with Peripheral arterial disease. NEJM 1992;326:381–6; Newman AB, et al. Morbidity and mortality in hypertensive adults with a low ankle/arm blood pressure index. JAMA 1993;270:487–9)
11 (Murabito JM, et al. Temporal trends in the incidence of intermittant claudication from 1950 to 1999, Am J of Epidemiol 2005;162:430-7)
16 (O’Hare AM, et al. High prevalence of Peripheral arterial disease in persons with renal insufficiency: results from the National Health and Nutrition Examination Survey, 1999-2000. Circulation 2004;109:320-3)
A. Richey Sharrett, MD, DRPH
Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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