Why your zip code matters when it comes to diabetic amputationsTen years ago, while working as an attending physician, Dr. Carl Stevens noticed a disturbing pattern: the majority of his patients with diabetes who acquired infections requiring amputation were from low-income backgrounds, while his diabetic patients from wealthier communities rarely needed such drastic treatment. High blood sugar can damage nerve fibers in the toes, feet and legs, which means people with diabetes are more susceptible to lower limb infections. Left untreated, these infections can lead to amputation. Stevens assembled a team to study the subject.
The team found hot spots of diabetic amputations, with the lowest-income neighborhoods facing amputation at rates 10 times greater than their high-income neighbors. The results were released this month in the journal Health Affairs. In his article, Dr. Stevens concludes that greater access to health services and education could likely reduce the disparity.
NEWSHOUR: Explain why people with diabetes are at a higher risk for amputations.
DR. CARL STEVENS: There are three main reasons for that, and this all applies to diabetes that's poorly-controlled. [The problem] can be somewhat delayed or ameliorated if they get good care.
Patients with diabetes have damage to the blood vessels in the legs and feet, both the large arteries that carry blood and the smaller vessels. So they begin with not very good circulation in the feet. Then, many develop what's called neuropathy, nerve damage in the hands and feet. So very often, they can't feel their feet or detect when they've developed a blister or a small cut on the foot until an infection has already been established there. And then the third factor is that immunity is reduced in diabetic patients, so their white blood cells just have more of a challenge trying to fight a bacterial infection, and it's mostly bacterial infections that result in these amputations.
So between the vascular damage, the nerve damage and the reduced immunity, that's what adds up to the high-risk situation with any kind of a foot problem.
NEWSHOUR: When did you first notice a correlation between poverty and high amputation rates?
DR. CARL STEVENS: I've spent my entire clinical career at Harbor-UCLA, which is a safety-net hospital. What led to my interest in this was seeing so many really young patients come in with these very advanced foot infections, and then hearing the surgery residents explain to them that, in order to save your life, because these infections spread very quickly, we need to take off your toe or your foot or your leg. So that was the genesis of the project. Then I and my co-authors decided to look more systematically at the relationship between income and the risk of losing a foot to diabetes.
NEWSHOUR: Explain what you mean by a "safety-net hospital".
DR. CARL STEVENS: The safety-net hospitals typically are the public hospitals. In the case of Los Angeles, Harbor-UCLA Medical Center is one of three full-service, public hospitals where patients can be seen regardless of their insurance status or ability to pay. There are other safety-net hospitals that function in low-income areas, but aren't public. And then there's a network of clinics that are available to patients with low incomes and often to patients without medical insurance. Some of those are privately run, and others are owned and operated by the county. In Los Angeles, we have an extensive outpatient clinic system.
The problem is, the supply of safety-net providers is not enough to meet the demand in the low-income areas, so there aren't enough primary-care offices for people to be seen in. As a result, they need to rely on the emergency department for their care, and they will often delay going in to the ER until they have quite an advanced infection, and it can't be cured with antibiotics, so a portion of the foot needs to be removed.
NEWSHOUR: So it's unusual to see such young patients with advanced infections?
DR. CARL STEVENS: Yes, if you're working in a more affluent hospital, it would be very unusual to see a young person coming in with an advanced foot infection for a variety of reasons. In more affluent areas, patients have more access to care, but they also are much more aware and educated about their disease, and they tend to have the resources to take care of themselves more effectively.
The typical amputation that might occur in a non-safety-net, or a typical community hospital, tends to be among older patients with severe peripheral vascular disease, from a variety of causes, and diabetes might be a contributing factor, but there are others there as well. Elevated cholesterol contributes to that, smoking is a very important factor in the development of peripheral vascular disease. In the older age range, amputation becomes more common just because the extent of vascular disease is more severe.
But I have seen patients in their 30s and certainly patients in their 40s come in with late-stage foot infections and go on to require amputations. And really, I think that's what spurred my initial interest: fairly routinely seeing people in the middle of their working years, in their 30s, 40s and 50s, come in and lose a foot to this disease.
NEWSHOUR: What can be done to address the problem?
DR. CARL STEVENS: With excellent care, the amputations are preventable. The main reasons the rates are lower in the higher-income areas is [people there] have access to good organized medical care, and they tend to have higher levels of health literacy: they are able to understand the instructions that are written for them on how to take their medications, they are better able to follow dietary advice and they tend to have their other risk factors, like high blood pressure and cholesterol under better control as well.
It's important to understand that the factors that feed into these preventable foot amputations in diabetics divide between delivery-system factors — the patients may or may not have health insurance, and even if they do have health insurance there is a shortage of primary care clinics and practices in low-income areas, so there's a supply-side issue there. But there's also a demand-side and health behavior difference, in how able lower-income patients are to participate in their own care and prevent complications from developing.
NEWSHOUR: You say in the paper that under-resourced hospitals rely more on amputation as a practice. Why is this?
DR. CARL STEVENS: An important point to understand is these data are from 2009, before the Affordable Care Act was implemented. At that time in California, the only way to get Medi-Cal, which is our state version of Medicaid, was to satisfy criteria for welfare. The typical adult who's not a single parent had no insurance coverage, unless they had employer-based insurance or could afford to buy insurance on the private market. Most of the patients in these low-income areas where the high amputation rates are had no insurance coverage at all, of any kind. For them, the only entry point to the delivery system is through safety-net facilities like public hospital emergency rooms and community clinics.
I want to be very careful about the statement that there are different practice patterns in safety-net hospitals with respect to the use of amputation. Limb-sparing treatment where the patient might get some dead tissue removed, but not the entire toe or not the entire foot, certainly is more complex and more time-consuming, and requires a lot more expertise to do. But we have programs that are limb-sparing, diabetic foot treatment available in our county hospitals here in Los Angeles. I definitely don't want to leave the blanket impression that if you go to a safety-net hospital they're just going to take off your foot, where somewhere else they won't. You might get better treatment.
NEWSHOUR: In this study, you mapped amputation rates according to geography, and located amputation "hotspots." What are the policy implications of this?
DR. CARL STEVENS: Neighborhoods have certain characteristics that allow the households in that neighborhood to produce good health outcomes. In other words, the environment is as important as the individual, in some ways … We do have a medical safety net in this country, and we have a pretty good one in Los Angeles County, because we have a very well-developed county hospital system. But that safety net is frayed, and it has holes in it that are worse in certain neighborhoods.
That's where the factors come together of relatively poor access, a relative lack of sophistication in understanding what diabetes is, how to treat it and how to manage it, and a lack of access to healthful foods and diet. The [lower-income] neighborhoods are inherently unhealthy, because most of the food that's available is through fast-food stores or liquor stores or small storefront markets. There's not a lot of fresh produce and whole, healthful foods available. So the factors that contribute to diabetes and complications cluster in neighborhoods, just as amputations are expected to.
On a policy level, different strategies are needed in those neighborhoods than might be possible in neighborhoods where levels of health literacy are higher, where fewer language barriers exist to understand what the right thing to do is, and where there are healthful options for food and places to exercise.
NEWSHOUR: What would those neighborhood-level interventions look like?
DR. CARL STEVENS: You're starting to see some of them take place already. The safety-net clinics have received funding under the Affordable Care Act to begin creating what are called "patient-centered medical homes," where, in addition to a primary care physician, they'll have a team consisting of a nutritionist and a pharmacist and several lay health workers that will be able to explain the disease to the patients and really increase what's called self-efficacy, which is the ability to be active participants in managing the disease. I think a big improvement that's already underway is the availability and quality of organized, continuous care for patients with chronic conditions.
But what has not been addressed, and needs to be, is how to get physicians and other health professionals to go and practice in those areas. We need to substantially change the incentives system so that it rewards primary care practitioners that are willing to practice especially in underserved areas. Probably, if you want to do that in a cost-neutral fashion, that means dialing back on some of the specialty-care spending that we do as a nation.
And then there are lots of creative initiatives underway for how to get farmers markets or supermarkets built into these neighborhoods so that they'll have access to healthful food, and how to create more safe green space, exercise grounds, bike paths, and other facilities that would encourage people to adopt a healthier lifestyle. I think those are all the policy pieces that need to fall into place before you make a really big dent in the disparity in the amputation rates.
NEWSHOUR: Your paper cites other work on the ethnic disparities in diabetes outcomes. Did your research touch upon the ethnic component of geographic distribution?
DR. CARL STEVENS: Our work just touches upon that. It's not a major theme of this piece. There is an ethnic disparity there, but we don't want to make too big a deal out of that because there are so many other factors that co-vary with race and ethnicity, such as access to good primary care and access to healthy food and health behaviors. Race alone does not explain these differences, but there are racial patterns that can be discerned in the data.
NEWSHOUR: Can your research be expanded beyond California? Are there national implications here?
DR. CARL STEVENS: This could be studied in Medicare right away. Nationwide data to expand this study exists, especially for the Medicare age group. I think the biggest national implication is, this is one example of a terribly debilitating health outcome that is preventable but that our current delivery system and education system does not succeed in preventing.
The main policy point that we're trying to make with this paper is that these preventable, serious, adverse consequences of limited access to health services, health education and other important inputs, are more serious than the typical American knows of. There's nothing about these amputations on the evening news, usually. But when people become aware of the disability that an amputation causes, and the fact it is preventable with good care, in a country that spends more dollars on health care by a vast amount than any other nation, a tenfold difference in amputation rates is just an unacceptable thing to most Americans.
Regardless of what your political inclinations are, or your specific opinion about the Affordable Care Act, I think it's just morally and ethically unacceptable to have people undergoing preventable limb amputations because they can't get the cure that they need. That is the take-home story, and it argues for doing everything we can, creatively, to improve access and make good care available to all.
This interview was edited lightly for clarity.