Secondary Prevention and Mortality in Peripheral Artery Disease: National Health and Nutrition Examination Study, 1999 to 2004
How many adults in the United States have peripheral artery disease (PAD), and what is the frequency and effect of appropriate preventive therapy use in these patients?
The authors analyzed data from the National Health and Nutrition Examination Survey (NHANES), an ongoing series of surveys and examinations conducted by the National Center for Health Statistics since the 1960s, using a multistage survey and examination scheme. The authors analyzed data from the 1999 to 2004 NHANES surveys, with mortality follow-up through December 31, 2006. Mortality status was determined using a probabilistic record match with the National Death Index, using demographic identifiers. PAD subjects were defined as those with an ankle-brachial index ≤0.90. Data on the use of statins, angiotensin-converting enzyme inhibitors, and aspirin were assessed and reported. The primary outcome was all-cause mortality.
Among the 7,458 eligible participants ≥40 years of age, the PAD prevalence was 5.9 ± 0.3% (mean ± standard error), which corresponds to roughly 7.1 million US adults having PAD. In this group, statin use was reported in 30.5 ± 2.5%, angiotensin-converting enzyme inhibitor use in 24.9 ± 1.9%, and aspirin use in 35.8 ± 2.9% of PAD patients. After adjustment for age, sex, and race/ethnicity, PAD was associated with all-cause mortality (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.9-2.9; p < 0.0001). After excluding subjects with known cardiovascular disease, subjects with PAD had higher mortality than those without (HR, 1.9; 95% CI, 1.3-2.8; p = 0.001). Among PAD subjects without cardiovascular disease, use of two or more of the evaluated preventive therapies was associated with significantly lower all-cause mortality (HR, 0.35; 95% CI, 0.20-0.86; p = 0.02).
The authors concluded that millions of US adults with PAD are not receiving secondary prevention therapies. They also concluded that treatment with multiple preventive therapies is associated with reduced all-cause mortality.
The NHANES is a wealth of clinical information generalizable to the entire US population, and continues to be a source of important epidemiological and clinical observations. The current well-designed study uses data from NHANES to tell us three important things about PAD patients in the United States: 1) a lot of people in this country have PAD (about 7.1 million adults); 2) a significant number of these patients are not receiving appropriate secondary prevention therapies; and 3) the use of multiple secondary prevention therapies in PAD patients (even without known cardiovascular disease) is associated with significantly reduced mortality. These data reinforce the importance of, and the relative lack of attention to, assuring that patients with PAD are identified and that they receive indicated secondary prevention therapies. There is a lot of room for improvement in the care of PAD patients in this country.
Keywords: National Center for Health Statistics (U.S.), Follow-Up Studies, Secondary Prevention, Peripheral Arterial Disease, United States
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