The number of people around the world with peripheral artery disease (PAD) increased by a dramatic and troubling 23.5 percent between 2000 and 2010, according to a major study published in the Lancet medical journal last week. PAD is a condition in which blood flow to the limbs, most commonly the legs, becomes restricted, severely limiting a person’s ability to walk. People with PAD are at increased risk of having a leg amputated due to gangrene from a sore that won’t heal. They are also at increased risk of experiencing a life-threatening heart attack or stroke.
Although the study found that 70 percent of individuals with PAD live in low- or middle-income countries, PAD is still a serious — and increasing — health problem in high-income countries. At least 8 million people in the U.S. have the disease, according to the Centers for Disease Control and Prevention. Yet, as the Lancet study and an accompanying commentary point out, PAD remains a relatively neglected disease in high- as well as lower-income countries, despite its startling statistics. PAD takes more lives globally each year than HIV/AIDs. It also leads to many more leg amputations than military conflicts or abandoned land mines.
Indeed, the commentary’s two University of Minnesota authors, cardiologist Dr. Alan Hirsch and epidemiologist Sue Duval, note that each year PAD results in more than 150,000 limbs being amputated in the U.S. alone, including 1,000 in Minnesota. By comparison, an average of 163 soldiers serving in the Afghanistan and Iraq conflicts underwent a major leg or arm amputation each year during 2001 to 2011.
In a phone interview last week, MinnPost talked with Hirsch about PAD and why it’s such an overlooked disease by the public and policymakers. (Surveys have found that only about 25 percent of Americans are aware of the disease.) The following is an edited transcript of that interview.
MinnPost: What is peripheral artery disease?
Alan Hirsch: It’s defined by the blockage of arteries by plaque anywhere outside the heart or the brain. It’s most frequently recognized when it occurs in the legs. It’s a close relative of artery blockages in the heart or the brain.
MP: Why is it a serious health problem?
AH: Whenever any artery is damaged, even in the slightest, the short-term risk of a series of bad things happening is high. [With PAD], there is a limitation of muscle blood flow and a walking impairment that is very clinically challenging. And if it’s very, very bad, then just like blockage in the heart can cause heart attack and a blockage in the brain can cause stroke, then the skin [in the legs or feet] itself can die and cause ulcers, gangrene and lead to amputation.
MP: The study mentions that peripheral artery disease is the third-leading cause, behind heart disease and stroke, of disability due to poorly functioning arteries.
AH: It’s often ranked third, but I don’t think that we can really rank them one, two and three. Society has been geared up for 30 or 40 years to detect heart disease, and so we find a lot of it. But there’s extremely low awareness of peripheral artery disease. It’s more or less the same disease in three different places. We just don’t tend to listen to our legs.
MP: How prevalent is the disease?
AH: We’ve known for 25 years at least that PAD was amongst the very most common diseases of aging. How common? A disease that affects 5 to 8 percent of adults over 50, or as many 20 to 25 percent of adults over 65 is nearly ubiquitous. In other words, every family essentially has an older member who has PAD. So if you’re sitting at the Thanksgiving table and looking at five older family members, one of the five has it, but it’s very, very likely they don’t know it. In the U.S. that number comes out to be 8 to 12 million individuals. In Minnesota the number has not been calculated, but it’s probably many hundreds of thousands. [The Lancet study] has calculated a minimal number in excess of 200 million globally. So it’s everywhere. It’s as common as trees.
MP: And, according to this new study, the prevalence of the disease has increased by almost a quarter over the past decade.
AH: Yes. That’s one of the key points. I don’t think we know the exact reasons, but we have enough reasons to be concerned. The article noted that because people live longer in the low- and middle-income countries, there are just more humans around in the world, and the price of longevity is exposure to chronic disease. But that’s not a benign exposure. In other words, you shouldn’t have to pay a price of another disease just by living longer.
The other reason [for the disease becoming more common] is clearly that we’re not exactly getting older healthily. The exposure to smoking everywhere in the world continues, and, obviously, the rise in obesity and diabetes are also known to make people age unhealthily. That raises the question as to whether survival to older age without health is really sustainable. Is it really what we want when we try to prolong human life?
MP: The risk factors for this disease include smoking, obesity and diabetes. Would you categorize this as a lifestyle disease?
AH: I think it’s a horrible term. I don’t know what it means. Is it self-imposed? Is it a choice? Is it modifiable? I don’t think it’s a term that creates any sense of control or optimism. You’re right, a lifestyle disease is a non-communicable disease that is [linked to] exposures to societal factors or lifestyle. But the culture in the society in which we live is not entirely our choice. So if you’re a young woman in central Minnesota or downtown St. Paul and your friends smoke and you become addicted at age 14 or 15, which is the average age, do you blame lifestyle or do you blame exposure to wrong messages and the availability of toxic substances?
Just as gunshot wounds aren’t a lifestyle disease, I hate to think of heart disease and stroke and PAD as lifestyle diseases when what we eat, how we exercise and what we smoke is environmentally created, without volition. We don’t fully get to choose. On the other hand, we are able to control it. So that’s the good news.
MP: What are some of the myths about PAD?
AH: In a world where everybody wants very quick messages and tweets and the shortest possible commercials and quick answers, then that leads to statements that are not fully true and that become myths. For many decades it was thought that PAD was a disease of men, primarily because in the ’60s and ’70s the U.S. war veterans, who were addicted to tobacco during the war, came back, and it was a disease of men. But it is now well known, and this study again collaborates, that PAD is gender equal or, if anything, it [places] a higher burden on women. In Minnesota and in the U.S., physicians do not always think to measure the pulses of women who have PAD-likely symptoms. Instead, they tend to think about joint problems or orthopedic problems, although eventually, after one to three years, the disease will get recognized. So gender-based biases exist.
The other myth is that although it’s true that PAD is more common in older people, it’s also true that, like heart disease and cancer, it can affect people in their thirties. I will be meeting [with a patient] later today who is in their young 20s. PAD is so common that even if it affected only 1 percent of 40-year-olds, that’s a lot of people.
MP: What are the disease’s key symptoms?
AH: For individuals who are either fortunate — or unfortunate — to have recognizable symptoms, which is maybe between 10 to 40 percent of the affected population, the most common hallmark system is exertional leg-muscle fatigue or discomfort that occurs at a reproducible distance when walking and that resolves promptly and certainly within 10 minutes of stopping exercise. That symptom is called claudication. It’s a bad feeling.
A very tiny fraction of people, probably just a few percent of the total population affected, [will be diagnosed when] a tiny cut or sore on the feet or the toes doesn’t heal within a month. Most cuts heal within one to two weeks. PAD is the most common cause of non-healing wounds or gangrene. Thankfully, it’s rare. But 1 or 2 percent of 12 million people [in the U.S.] is an awful lot of cases of gangrene.
Probably half of the individuals who are clearly affected and have the disease won’t feel any recognizable symptoms. That’s no different than a woman having a right-breast adenocarcinoma and not knowing it. Or a person could have HIV and for a while not be aware.
MP: You note in your commentary that more than 4,000 people around the world either died or lost a limb due to landmines in 2011 and that a total of 1,631 American service members lost an arm or a leg as a result of combat in Afghanistan or Iraq during the past decade. Those losses have received a lot of public attention. That’s not the case for PAD-related amputations, yet their numbers are much higher.
AH: Yes. We lose as many legs from PAD each year in Minnesota as we more or less have lost by American serviceman in many of our wars over a decade. And we are a healthy PAD state. There are many, many states that are much worse than Minnesota. But our societal approach is to put people [with PAD-related amputations] away into transitional care facilities and not look at them because it’s painful to see. I care about our war veterans, but I care about everybody who might be at risk who might lose a leg to amputation. And PAD is the most common cause of amputation in the world.
MP: You also note that there are six times more people living with PAD around the world than are living with HIV, which has been declared a pandemic disease. PAD also has a much higher death rate. So why is PAD not on our radar screen?
AH: I used to be more patient and tolerant about ignorance, bias and lack of foresight in health care. But I’ve lost a lot of my patience. The analogy to HIV is important. When I was a trainee in California in my medical school and residency years, HIV was a stigmatized disease that only affected a small subgroup of individuals for which every level of government and physicians were afraid and really did very little to help. It wasn’t until individual HIV patients stood up for themselves and demanded attention that the pandemic of HIV was really cared for. After that, there were investments in research and support groups, and one of the most horrifying diseases of our lifetime was made tolerable although still very, very difficult.
Individuals with PAD basically have no place to go that would serve as their advocate. In a Western democracy, or in a state like Minnesota or anyplace in the world, when people speak up for themselves, whether it’s protesting in the streets of a country or in our own state capital, that makes a difference. So if people who are affect read your article and decide to organize, that would be great. And if national or Minnesota businesses would like to use some part of their proceeds from caring for the disease to support advocacy groups, I would think that would be wise.
But to create room for PAD, the last major pandemic cardiovascular disease, in a society that’s weary of chronic illness, that’s tough. If this illness had been news in 1968, my guess is by now the problem would be solved. But we are now focused almost entirely on tiny event rates for heart disease and stroke and there is very little energy left for doing anything new. Public health efforts are often near exhaustion and underfunded. In the last five years especially there has certainly been a relative lack of support for major new prevention efforts, although there is an opportunity in the Affordable Care Act to do so.
It would certainly make a lot more sense to prevent PAD than to spend more than $21 billion a year for [PAD-related] end-stage care. That’s what the U.S. spends. I don’t think we want the low- and middle-income countries to emulate that — and to what end? It doesn’t block all the suffering.
MP: The direction of this illness will become unsustainable.
AH: It’s not going to become unsustainable. It is already unsustainable.
MP: What can individuals do to lower their risk?
AH: Societies and nations become strong and prosperous when children and adults focus on cultural behaviors that create life energy, etc. [Ensuring that] individuals are not exposed to high blood pressure, high cholesterol, diabetes and smoking could essentially abolish most cardiovascular disease, 70 to 80 percent of it, including PAD. That’s what people could do within their families.
I always say, you often know your loved one’s birthday or their favorite food. But love means also protecting their health, and people are always healthier when someone is looking after their health. So knowing your loved one’s cholesterol, smoking habits and blood pressure, specifically, is as important as knowing their birthday. And you can celebrate [together] having those seven healthy lifestyle behaviors as outlined by the American Heart Association [be active, control cholesterol, eat a healthy diet, manage blood pressure, maintain a healthy weight, control blood sugar and don’t smoke].
Achieving health is not a personal burden. It’s a family and community obligation that is easily achieved when we work together. I really believe that.