This article is more than 5 years old. Information may no longer be current.
USPSTF: Insufficient evidence exists showing benefits of ankle-brachial index for PAD
The U.S. Preventive Services Task Force has given a class I indication for the use of ankle-brachial index to screen adults for peripheral artery disease and CVD risk, as there is not enough evidence to support or oppose the method, according to a draft recommendation statement released by the task force.
The new recommendation was drafted to replace a 2013 USPSTF recommendation.
“Although the current evidence review was expanded to include a broader population and rage of interventions, the USPSTF has not changed its recommendation from an I statement,” the task force wrote in the statement.
Prevalence of PAD
In the United States, 5.9% of the population aged 40 years or older has an ankle-brachial index less than 0.9, but the number may be inaccurate because more than half of patients with a low ankle-brachial index have atypical symptoms or are asymptomatic, according to the statement.
There is adequate evidence that ankle-brachial index accurately detects PAD in symptomatic patients, but few data exist on its accuracy in those who are asymptomatic and would benefit from treatment. Inadequate evidence is available on the benefits of screening and treating asymptomatic patients for PAD, and adequate evidence highlights the minimal harms of screening itself such as anxiety, costs, false-positive results and exposure to contrast dye.
In asymptomatic patients who have not been diagnosed with CVD, PAD or severe chronic kidney disease, the USPSTF suggests taking certain factors into consideration before screening with ankle-brachial index. These factors include potential harms, potential preventable burden and current practice.
Major risk factors for PAD include older age, current smoking, diabetes, high cholesterol, high BP, physical inactivity and obesity. Men are more likely to develop PAD compared with women, although that is no longer relevant after adjusting for age.
In clinical settings, resting ankle-brachial index is generally used to detect patients with PAD, although few data focus on the accuracy of the test in patients who are asymptomatic. Physical examinations are often used in this patient population, but it has low sensitivity and its clinical benefits and harms have not been well-studied.
PAD treatment
Treating PAD should be focused on improving outcomes in those who are symptomatic, although many of these patients may be recommended for such treatments due to their increased risk for CVD.
To conclude whether screening patients for PAD with ankle-brachial index improves clinical outcomes, more randomized trials are needed that compare screening with no screening, the task force wrote. Other studies should also focus on the patients who are potentially at increased risk for PAD who are not reducing their CV risk through interventions, according to the report.
“For people with symptoms of PAD, the [ankle-brachial index] can be used for diagnosis,” Alex Krist, MD, MPH, professor of family medicine and population health and director of community-engaged research at the Center for Clinical and Translational Research at Virginia Commonwealth University in Richmond, an active clinician and teacher at Fairfax Family Practice Residency in Virginia, co-director of the Virginia Ambulatory Care Outcomes Research Network in Richmond and a task force member, said in a USPSTF bulletin. “However, more evidence is needed to determine if the [ankle-brachial index] can accurately identify PAD in people without signs or symptoms.”
The USPSTF’s draft recommendation statements can be viewed on the task force’s website: www.uspreventiveservicestaskforce.org. Comments will be accepted until Feb. 12. After comments are received, the task force decides whether to incorporate them and issues a final recommendation. – by Darlene Dobkowski
Disclosure: Krist is a member of the USPSTF.
Perspective
Back to Top
This will further reduce the use of the ankle-brachial index as a completely safe method of detecting atherosclerosis.