Racial Disparities in Cardiovascular Disease - Episode 5

Diabetes and Heart Disease Among Minority Populations

Keith C. Ferdinand, MD, FACC, FAHA, FASH, FNLA: I’m Dr. Keith C. Ferdinand, professor of medicine at the Tulane University School of Medicine in cardiology at the Tulane Heart and Vascular Institute.

Today I’m talking about diabetes and cardiovascular care. If you look at persons who have diabetes—specifically, type 2 diabetes—the No. 1 cause of death is not poor control of glucose but actually ischemic heart disease. Persons with diabetes die more from ischemic heart disease than from any other cause.

If we look at the control of glucose itself, it may have benefits specifically for microvascular disease; that is, retinopathy, kidney disease, and maybe even peripheral arterial disease. But for macrovascular disease, major heart attacks, and dying from heart failure, this is the most common cause of death for adults with diabetes. Some of the newer data using, for instance, the SGLT2 [sodium-glucose cotransporter-2] inhibitors with the EMPA-REG OUTCOME trial show that there is a decrease in overall cardiovascular death and total mortality and a decrease in hospitalization for heart failure.

In the same lines with canagliflozin in the CANVAS study, there was a 40% decrease in the aggregate of a progression to end-stage renal disease, renal failure, and death. Therefore, the appropriate treatment of persons with type 2 diabetes is more than just simply controlling glucose. In fact, some of the studies now suggest that there will be a worldwide epidemic of diabetes—as many as 400 million people across the globe—by 2025. There will not be enough endocrinologists to actually control this particular condition. Unfortunately, racial and ethnic minorities are often underrepresented in clinical outcomes trials. Therefore, I led an initiative to have a study done in a high-risk population who had both hypertension and type 2 diabetes, African Americans. In this particular study with 150 persons who had uncontrolled diabetes with a hemoglobin of A1C from 7 to 11, and uncontrolled hypertension with systolic blood pressure of 140 to 180, we enrolled patients and randomized them to either placebo or empagliflozin starting at 10 mg and increasing to 25 mg.

The patients then had ambulatory blood pressure monitoring done. Because empagliflozin is an antidiabetic medicine, the primary outcome was 24 weeks decrease in hemoglobin A1C, which was met from a baseline hemoglobin A1C of approximately 8.5, with a decrease of 0.78.

Nevertheless, there were prespecified outcomes specifically related to blood pressure using ambulatory blood pressure monitoring, which is a valid way of measuring the effects of blood pressure for any medication. We saw a statistically significant decrease of approximately 6 mm in the systolic blood pressure on the ambulatory blood pressure monitoring at 12 weeks, which was maintained for 24 weeks.

The clinic blood pressure was decreased approximately 4 mm of mercury. This was not statistically significant but clinically meaningful. Even more importantly, after 24 weeks the clinic blood pressure also decreased statistically. There was also a loss in body weight with empagliflozin. Therefore, the SGLT2 was maybe beneficial in African American patients who have both hypertension and diabetes.

Although not a cardiovascular outcomes trial, our abstract, published in JACC [Journal of the American College of Cardiology], suggested that there may be a real benefit in blood pressure reduction and control of glucose with the bonus of some degree of weight loss using empagliflozin, an SGLT2 inhibitor, in African Americans who had both hypertension and type 2 diabetes.

This is an important study. Despite its small sample size and the fact that there were no cardiovascular outcomes, they suggest that empagliflozin can be used safely in this population. African Americans are known to have an increase in hypertension and comorbid diabetes. And, in fact, 80% of persons who have type 2 diabetes also have hypertension, and this is even higher in the black population.

In the REGARDS study, a large southern cohort of over 30,000 persons, just 30% of African Americans who had both diabetes and hypertension had their blood pressures controlled to less than 130/80. Empagliflozin has been shown to be beneficial in the EMPA-REG study. Nevertheless, in the study that we just completed, control of cardiovascular risks, specifically diabetes, glucose, and blood pressure can be used in this particular population.

I’m Dr Keith C. Ferdinand talking about diabetes and its relation to cardiovascular care.

Transcript edited for clarity.