For patients with diabetes, cardiovascular disease should be a top priority.
Nathan D. Wong, PhD, director of the Heart Disease Prevention Program at the University of California, Irvine, is a co-author of the “Heart Disease and Diabetes” chapter in the NIDDK publication Diabetes in America, 3rd Edition. Here he talks about the importance of broadening the clinical focus of diabetes care from hemoglobin A1C to also include other risk factors for cardiovascular disease common in patients with diabetes.
Q: Why is it so important to talk about heart disease with patients who have diabetes?
A: More than two-thirds of patients with diabetes will die of cardiovascular-related illnesses such as coronary heart disease, stroke, heart failure, and peripheral arterial disease. For women with diabetes, the risks for different forms of cardiovascular disease are three to seven times greater compared with women who do not have diabetes. For men with diabetes, the risk is two to three times greater.
We are doing a poor job of managing heart disease in people with diabetes in this country and throughout the world, despite many advances in therapies over the past 30 years. We still have a very small percentage of people with diabetes—
Many of these factors have an impact on risk for certain microvascular complications associated with diabetes such as retinopathy, nephropathy, and neuropathy. But these factors also affect risk for macrovascular complications such as heart disease and stroke.
Q: How does cardiovascular risk differ for type 1 and type 2 diabetes?
A: When people are diagnosed with type 2 diabetes, they often already have hypertension and dyslipidemia. For people with type 1 diabetes, the diagnosis generally comes when they’re much younger, so they aren’t yet at significant cardiovascular risk. There’s a true opportunity to help prevent them from developing cardiovascular risks in the first place, rather than trying to catch up with these factors after they’ve developed and are more difficult to control.
Q: What are the benefits of keeping all the cardiovascular risk factors at target levels?
A: The Steno 2 clinical trial found a 53% risk reduction in cardiovascular outcomes for people with type 2 diabetes who were intensively treated for risk factors, compared with participants in the control group. In a follow-up paper, the researchers reported on mortality rates after 13 years. They found it was significantly lower for the intensively treated group. Just 30% had died, compared with 50% of the conventionally treated group.
In an observational study, we pooled data on people with diabetes from three different clinical trials to show an approximately 60% lower risk for developing coronary heart disease or cardiovascular disease in people with diabetes who were at target levels for LDL cholesterol, blood pressure, and hemoglobin A1C. This suggests we can possibly reduce the risk of future heart attacks or strokes by more than half, if we ensure that these factors are controlled.
Q: What does this mean for diabetes care?
A: We still have a lot of work to do to get the word out that diabetes is really a cardiovascular condition. Most people with diabetes are not dying from retinopathy or neuropathy; they are dying from cardiovascular disease. This is not to trivialize the microvascular complications. Obviously, neuropathy or retinopathy can significantly affect quality of life. But in terms of what a person with diabetes eventually will die of, it’s cardiovascular disease. Patients and their health care providers really have to better understand that controlling diabetes is much more than controlling blood sugar.
Certainly, managing glucose is critical to prevent microvascular complications, in particular. There is strong epidemiologic data that adverse cardiovascular outcomes are greater in people with higher levels of hemoglobin A1C, but the evidence is less striking for improving cardiovascular outcomes from glucose control alone. And in fact, the ACCORD trial actually showed increased cardiovascular mortality to occur when targets were set too aggressively for hemoglobin A1C.
Q: How can the message on cardiovascular risk factors reach more health care professionals?
A: I think there’s tremendous opportunity to advance professional education to help improve cardiovascular outcomes in people with diabetes. And this, of course, can be accomplished with lifestyle changes. But few people with diabetes see a dietician and/or exercise physiologist as frequently as they should to help them with their diabetes self-management. These allied health care providers are not traditionally part of the health care team as much as they should be, because reimbursement is not always available for their services. Physicians need to know that these resources exist, and that they can also prescribe lifestyle improvements such as walking or eating more vegetables.
At professional meetings, I've asked for a raise of hands: “How many of you physicians have heard of the American Medical Association?” Virtually all of them have. Then I ask, “How many of you have heard of the Academy of Nutrition and Dietetics?” Very few have, yet this is a very powerful group. Specifically, the Academy’s Sports, Cardiovascular and Wellness Nutrition dietetic practice group includes close to 10,000 people around the country. The American College of Sports Medicine includes exercise physiologists. But there's a disconnect. We need to help physicians know that these other providers, who are key to patients’ success in managing their diabetes and cardiovascular risks, exist.
Q: How can cardiologists contribute to better care for patients with diabetes?
A: The American College of Cardiology advocates for cardiologists to learn more about how to manage diabetes. This is largely fueled by the fact that we now have newer medications that are shown to reduce cardiovascular events in people with diabetes. These drugs are not the most powerful A1C-lowering agents, but they’re the only agents shown to have benefits in terms of cardiovascular outcomes. The sodium-glucose cotransporter-2 (SGLT2) inhibitors, in particular, have the dramatic effect of reducing heart failure-related hospital stays by more than 30%. Equally exciting are the glucagon-like peptide-1 (GLP-1) receptor agonists, which seem to have more of an anti-atherosclerotic effect.
Both of these therapies have been incorporated into several guidelines. The American College of Cardiology, the American Association of Clinical Endocrinologists, the American Diabetes Association, and the American Heart Association recommend these therapies specifically for people with pre-existing diabetes and cardiovascular disease.
But it’s mainly the specialty community that has started to use these therapies. We need to increase efforts to communicate the value and the indications of these therapies among primary care providers, too.
Q: What advice do you have for health care professionals so that they can better help their patients with diabetes manage the cardiovascular risk factors?
A: Providers and patients with diabetes alike need to understand that cardiovascular disease should be their main concern. It takes a concerted approach to manage all the relevant risk factors to significantly improve outcomes. We’re talking about a multidisciplinary cardio-diabetes care team that includes lifestyle specialists—dieticians and physical activity experts—as well as other appropriate specialists, including the endocrinologist and the cardiologist, and, in many cases, the primary care provider at the center of the patient’s care.
Health care professionals also need to motivate patients to take greater charge in their health care. Shared decision-making is very important in starting new therapies and managing lifestyle changes.
What has been your experience addressing cardiovascular risk in your patients with diabetes? Tell us below in the comments.