Misconceptions About Diabetes Management in Cardiology
Yehuda Handelsman, MD
Metabolic Institute of America
Handelsman Y. Misconceptions about diabetes management in cardiology. [published online August 6, 2019]. Cardiology Consultant.
Working within a multidisciplinary team, I am often faced with questions from my colleagues in cardiology and nephrology. The first question they ask is, “Why are you so focused only on glucose?” That is a misconception. We endocrinologists really focus on a comprehensive approach to managing diabetes. We address the dyslipidemia, hypertension, obesity, other cardiovascular (CV) risks, and also glucose in patients with diabetes. From a cardiologist’s point of view, they only tend to see the heart in patients with diabetes, which is inappropriate in managing these complex conditions, and disregard the eyes, kidneys, and amputations.
In 1998, the East West Study1 showed that people with diabetes had an equivalent risk for cardiovascular disease (CVD) as did people who had myocardial infarction (MI).
This notion was frequently challenged by cardiologists who thought people with diabetes were not CV risk equivalent and that many patients with diabetes did not have a risk for heart disease. That is where they were wrong. Indeed, not everyone with diabetes has the same risk for CVD; some may be equivalent, some may have very high risk, and some may have moderate risk. However, the fact is that patients with diabetes, even if not having risk equivalent, have a much higher risk for CVD than the general population. This took cardiologists in general a long time to understand.
Another question I receive a lot is, “What kind of heart disease do people with diabetes have?” There are all kinds of heart diseases present in patients with diabetes. Coronary atherosclerosis leading to MIs, atrial fibrillation, sudden death, and congestive heart failure (CHF) are all more common among these patients compared with the general population. CHF with preserved function is a condition that many physicians, including cardiologists, do not understand and have difficulty diagnosing and managing the condition.
Once recent CV outcome trials with new glucose- and lipid-lowering medications showed reduction in morbidity and mortality in people with diabetes, the question then became, “Why would you use any other drugs besides SGLT-2 and GLP‑1 inhibitors to manage hyperglycemia in people with diabetes?” The answer is that obviously we will prescribe the drugs that will reduce CV events; however, many patients still need to have their high glucose controlled. For example, people with diabetes who have kidney problems may have to be on an SGLT-2 inhibitor, which has shown positive improvement of kidney function and reduction in macrovascular disease. But the glucose reduction will not be high enough, and these patients will need other medications.
Also, some patients who can benefit from treatment with GLP-1 inhibitors may not be able to tolerate the drugs. Therefore, we will again need to prescribe medication without CV outcomes. We cannot allow a patient to have ongoing high glucose levels, because we need to continue preventing the other complications of diabetes. In fact, if we allow patients to be exposed to long-term hyperglycemia, many of the CV complications will recur. Many patients with diabetes have insulin deficiency and must be treated with insulin, despite a risk for hypoglycemia or no superior CV outcome results. People who are taking SGLT-2 inhibitors have a higher risk for diabetic ketoacidosis (DKA), and they must have enough insulin to prevent the DKA. As such, it is clear that the person with diabetes must be managed with a variety of medications, often combination therapy, and may have to get medications without CV outcomes.
The Paradigm Shift
The main takeaway here is that people with diabetes are considered at very high risk for CVD, if they do not already have it. The paradigm shift occurred primarily among cardiologists, who now recognize this fact. Endocrinologists have worked hard to control the CVD risks, including glucose, among patients with diabetes, and now that we are adding cardiologists to the multidisciplinary team, it is important that they understand the full scope of the disease, as well.
Yehuda Handelsman, MD, is a practicing endocrinologist and the medical director of and principal investigator at the Metabolic Institute of America in Los Angeles, California.
- Haffner SM, Lehto S, Rönnemaa T, Pyörälä K, Laasko M. Mortality from coronary heart disease in subjects with type 2 diabetes and in nondiabetic subjects with and without prior myocardial infarction. N Engl J Med. 1998;339(4):229-234. doi:10.1056/NEJM199807233390404.