Minnesota, MN - The first-ever national survey about awareness of peripheral arterial disease (PAD) has shown that the US public is very poorly informed about this disease [1]. Dr Alan T Hirsch (University of Minnesota, Minneapolis) and colleagues for the PAD Coalition report their findings online September 17, 2007 in Circulation.

"PAD is barely known to one in four people," Hirsch told heartwire. "I think most healthcare professionals have always suspected a lack of awareness of PAD, and these data now quantify that lack of awareness in startling terms." Most worryingly, Hirsch and colleagues found that knowledge gaps about PAD were most prominent among individuals at the highest risk for the disease. They now hope to emulate the successes of past education campaigns in hypertension and hypercholesterolemia and raise awareness of PAD. "We have a perfect opportunity to avert tragedy. In 2007, are we able to learn from the lessons of the past and offer information directly to African Americans, the poor, the less well-educated, and those who are exposed to risk factors for PAD?" Hirsch wonders.

We have a perfect opportunity to avert tragedy.

Dr Valentin Fuster (Mt Sinai Medical Center, NY), who was not involved with the survey, told heartwire he was not at all shocked by the data. "I'm not surprised about the data obtained when in fact there is also a lack of knowledge at the physician level about patients who have PAD." But there is a simple solution, says Fuster, which is to educate doctors to use simple screening of the ankle/brachial pressure ratio to identify patients with PAD. "However," he says, "I've been around the world and asked doctors about who is using this test, and it's no more than 5%." But Fuster is optimistic that things can change: "I think we need more time, but it will not take too long until everyone is aware of this huge problem."

Hirsch and colleagues explain that lower-extremity PAD is common, affecting as many as eight million Americans and resulting in a fivefold increased relative risk of MI and a two- to threefold greater risk of stroke and total mortality than those without PAD. PAD has been recognized as a coronary heart disease risk equivalent in national guidelines, yet current data suggest that PAD detection and treatment are lower than for other forms of atherosclerotic arterial disease.

Thus, the PAD Coalition—a scientifically based consensus-driven group that works in partnership with the National Heart, Lung, and Blood Institute to foster increased awareness of PAD—has begun a national effort in the US to improve access to PAD-related health information. The current survey was conducted to establish a population-based baseline.

They surveyed 2500 people >50 years of age by telephone, with oversampling of blacks and Hispanics, measuring the demographic, risk-factor, and cardiovascular disease characteristics of the study population. They also assessed prevalent leg symptoms, PAD awareness relative to atherosclerosis risk factors (recognized as any positive response to either PAD or peripheral vascular disease), and other cardiovascular and noncardiovascular diseases, perceived causes of PAD, and perceived systemic and limb consequences of PAD.

They found that only 25% of respondents were familiar with PAD, "a rate significantly lower than for any other cardiovascular disease or atherosclerosis risk factor." And even within the "PAD-aware" cohort, knowledge was poor. Half of these people were not aware that diabetes and smoking increase the risk for PAD, and fewer than one in four knew that PAD is associated with an increased risk of heart attack and stroke. And only 14% knew that PAD could lead to amputation.

"These findings show that awareness of a disease does not necessarily translate to knowledge," says coauthor of the survey Dr Timothy Murphy (Brown University, Providence, RI). "If the public is uninformed about the devastating consequences and causes of PAD, they will be less likely to take steps to avoid it."

The survey also showed that only 18% of adults had ever undergone an ankle/brachial index (ABI) test, "demonstrating that use of the ABI and/or communication of its utility to at-risk populations remain very low," say the researchers.

Strikingly, patients with PAD are more likely to have a new ischemic event than those who have already had a coronary event.

Fuster says everyone at risk should undergo an ABI test "because only about 30% of those affected [by PAD] have clear claudication, and the others have unusual symptoms and no claudication at all. The ABI is extremely sensitive and extremely specific for peripheral vascular disease."

One of the problems, he believes, "is that people have become absolutely obsessed with coronary events, without realizing that when the legs are affected it's already a warning that the coronary event is coming. There is so much effort in trying to identify coronary disease, but not about what are the risks surrounding coronary disease that may be identified in the legs."

Dr Michael Criqui (University of California, San Diego), another coauthor of the survey, agrees. "Data have shown that doctors are much more likely to treat lipid abnormalities and other things in patients who have coronary disease than in those who have PAD. But in fact, strikingly, patients with PAD are more likely to have a new ischemic event than those who have already had a coronary event."

The new survey also asked people where they had obtained their information about PAD. "Perhaps it's no surprise that most learn about it from TV and magazines or from a friend," Hirsch told heartwire. "On the other hand, for a serious medical illness, it would seem that we'd want to live in a world where we link identification of a high-risk group to the healthcare professional discussing it. But so few hear about it from their healthcare professional (less than 20%). In fact, doctors, nurses, and pharmacists were hardly recognized as a source of [PAD] information."

So rarely is there any news on PAD that gets any high-level interest.

The media also has a large role to play, says Hirsch, describing the woeful coverage of a recent PAD trial presented at the European Society of Cardiology meeting in Vienna. "So rarely is there any news on PAD that gets any high level interest. Take, for instance, the getABI study reported recently in Europe, but no one knew about it. That seems to tell a story."

GetABI showed that PAD patients have a substantially increased risk of death—dying, on average, 10 years earlier than their peers—and that asymptomatic PAD patients are as much at risk as symptomatic ones, an important fact that was not previously appreciated.

Another factor that surprised the authors was that public familiarity of PAD in the survey was lower than that of multiple sclerosis (MS; 42% were aware of this), amyotrophic lateral sclerosis (ALS; 36%), or cystic fibrosis (CF; 29%). Hirsch told heartwire that while most people know someone who has MS and knowledge of ALS is gained from celebrities who have suffered from this illness, familiarity with CF is likely due to the success of health-promotion campaigns that have run for this exceedingly rare disease.

The last shows that large public-awareness campaigns can work "and provides hope to the media, governments, and physicians that it really doesn't take a lot of effort to modify awareness and knowledge. We hope there's a positive message in there somewhere," he says.

Hirsch says that they are trying to take their lead from the cholesterol and hypertension public-awareness campaigns. "We want to use data to drive this thing, and we will repeat this survey every two years until we have better grades. It's better not to guess, better to use data to drive messages," he concludes.