September 2005 | Vol. 23, No. 9

U.S. Preventive Services Task Force Recommendations on PAD and AAA

USPSTF Recommends Against Routine PAD Screening

The U.S. Preventive Services Task Force in August recommended against routine screening for peripheral arterial disease (PAD). The Task Force made the same recommendation when they last reviewed the evidence in 1996. The Task Force found no evidence that detecting peripheral arterial disease earlier leads to better health outcomes, especially in individuals who may suffer from the disease and don't experience symptoms.

Rationale: The USPSTF found fair evidence that screening with an ankle brachial index (ABI) study can detect adults with asymptomatic PAD. The evidence is also fair that screening for PAD among asymptomatic adults in the general population would have few or no benefits because the prevalence of PAD in this group is low and because there is little evidence that treatment of PAD at this asymptomatic stage of disease, beyond treatment based on standard cardiovascular risk assessment, improves health outcomes.

However, the USPSTF also found fair evidence that screening asymptomatic adults with an ABI study could lead to some small degree of harm, including false-positive results and unnecessary work-ups. Thus, the USPSTF concludes that, for asymptomatic adults, harms of routine screening for PAD exceed benefits.

USPSTF Recommendation for some AAA Screening

Earlier this year the USPSTF recommended one-time screening for abdominal aortic aneurysms (AAA) by ultrasonography in men aged 65 to 76 who have ever smoked.

Rationale: The USPSTF found good evidence that screening for AAA and surgical repair of large AAAs (5.5 cm or more) in men aged 65 to 75 who have ever smoked (current and former smokers) leads to decreased AAA-specific mortality. There is good evidence that abdominal ultrasonography, performed in a setting with adequate quality assurance (i.e., in an accredited facility with credentialed technologists), is an accurate screening test for AAA. There is also good evidence of important harms of screening and early treatment, including an increased number of surgeries with associated clinically-significant morbidity and mortality, and short-term psychological harms. Based on the moderate magnitude of net benefit, the USPSTF concluded that the benefits of screening for AAA in men aged 65 to 75 who have ever smoked outweigh the harms.

The USPSTF made no recommendation for or against screening for AAA in men aged 65 to 75 who have never smoked.

Rationale: The USPSTF found good evidence that screening for AAA in men aged 65 to 75 who have never smoked leads to decreased AAA-specific mortality. There is, however, a lower prevalence of large AAAs in men who have never smoked compared with men who have ever smoked; thus, the potential benefit from screening men who have never smoked is small. There is good evidence that screening and early treatment leads to important harms, including an increased number of surgeries with associated clinically-significant morbidity and mortality, and short-term psychological harms. The USPSTF concluded that the balance between the benefits and harms of screening for AAA is too close to make a general recommendation in this population.

The USPSTF recommends against routine screening for AAA in women.

Rationale: Because of the low prevalence of large AAAs in women, the number of AAA-related deaths that can be prevented by screening this population is small. There is good evidence that screening and early treatment result in important harms, including an increased number of surgeries with associated morbidity and mortality, and psychological harms. The USPSTF concluded that the harms of screening women for AAA outweigh the benefits.

The U.S. Preventive Services Task Force is an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services. Sponsored since 1998 by the Agency for Healthcare Research and Quality (AHRQ), the Task Force is the leading independent panel of private-sector experts in prevention and primary care. For additional information, please go to the USPSTF website at http://www.preventiveservices.ahrq.gov/#uspstf.