Since 2017, the United States has recognized Diabetes Heart Connection Day every November 9th during American Diabetes Month.¹ This national initiative aims to raise awareness about the link between diabetes and heart disease, 2 leading causes of death and disability worldwide.²

Most physicians are well aware of the overlapping factors between these 2 conditions, including metabolic dysfunction, inflammation, and oxidative damage. However, it’s helpful to review the dynamic interplay between diabetes and heart health, particularly regarding diabetes medications and cardiovascular outcomes. Here’s what you should know.

The Impact of Diabetes on the Heart

People with type 2 diabetes have double the risk of developing heart disease.¹ This risk increases the longer someone has diabetes—a fact that’s particularly concerning given the younger age of type 2 diabetes onset in recent years.^3,4 Over time, elevated blood sugar levels damage the blood vessels and nerves of the cardiovascular system.³ Around half of diabetes patients die from the complications of ischemic heart disease, heart failure, stroke, coronary artery disease, and peripheral artery disease.⁴

Hyperglycemia is associated with vascular complications. In addition, an excessive buildup of lipids in type 2 diabetes may produce insulin resistance in the heart muscle, along with fibrosis, and diastolic dysfunction. Researchers have also noted the hazardous effects of hypoglycemia on the heart due to poor diabetes management.⁴

Screening and Prevention Guidelines

Efforts to avoid or delay new cases of heart disease in people with diabetes are critical to public health. Primary prevention includes healthy lifestyle recommendations and the monitoring and control of blood sugar, blood pressure, and lipids.⁴

The American Heart Association and the American College of Cardiology developed a risk stratification tool for primary prevention in patients with type 2 diabetes who don’t have heart disease. They’re also working on a risk stratification tool for secondary prevention.

Another screening method, the Risk Estimator Plus tool, allows physicians to calculate the 10-year risk of atherosclerosis in diabetes patients ages 40 to 79. This tool accounts for the following factors:

• Age
• Blood pressure
• Diabetes history
• Drug use
• Lipid numbers
• Sex
• Smoking

Before 2018, the focus of prevention was centered around glucose control. The general consensus on goals for hemoglobin A_1c (HbA_1c) includes the following:

• less than 7% for most patients (less strict for older, frail patients)
• 6.5% or lower for those with an early diagnosis who don’t have atherosclerosis
• less than 6% during pregnancy, assuming the absence of hypoglycemia

Patients with heart failure and type 2 diabetes experience the lowest risk of death or hospitalization when HbA_1c levels fall between 7.1% to 8%. The risks increase at levels below 6% and above 8%.⁴

While glucose control is still the cornerstone of diabetes management, other risk factors should be carefully monitored, particularly blood pressure. High blood pressure accelerates cardiovascular disease, and the stakes are already too high for those with diabetes.

Achieving blood pressure levels of less than 120 mm Hg/70 mm Hg reduces mortality and promotes better cardiovascular outcomes in patients with and without diabetes. As a result, the American Heart Association advises intervention for any patients with blood pressures higher than 120 mm Hg/70 mm Hg. However, the treatment targets for patients with diabetes and hypertension may range from less than 130 mm Hg/80 mm Hg to less than 140 mm Hg/90 mm Hg, depending on the patient’s risk factors.⁴

Beyond these metrics, health care is gradually shifting to a more patient-centered approach. This approach encompasses multiple aspects of the patient’s metabolism and behaviors with an ultimate goal of precision medicine that’s highly targeted by additional factors like genetics and highly specific risks.⁴

How Diabetes Drugs Affect Cardiovascular Risk

Fortunately, just as many lifestyle interventions for diabetes management are good for the heart, diabetes medications have also demonstrated cardiovascular benefits. In one study, patients who were overweight who were newly diagnosed with diabetes experienced a 39% reduction in the incidence of myocardial infarction by taking metformin.

In addition, the long-term use of metformin (10 years) appeared beneficial for the primary prevention of heart disease. It’s considered appropriate therapy for those with diabetes, both those with and without existing heart disease, although more evidence is needed on the potential protective effects in secondary prevention.⁴

Recent studies show that sodium-glucose cotransporter 2 (SGLT-2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists lower the risk for heart failure and atherosclerotic heart disease regardless of the patient’s baseline HbA_1c levels.⁴

A meta-analysis of 3 studies on patients with diabetes and SGLT-2 inhibitors found the following:

• 11% reduction in major adverse cardiac events in patients with atherosclerosis
• 23% reduction in death or hospitalization from heart failure
• 45% lower risk of renal disease progression
• Reduction in cardiac arrhythmias and atrial fibrillation

GLP-1 agonists have demonstrated similar benefits in randomized control trials, with a systematic review and meta-analysis study showing:

• 14% fewer major adverse cardiac events
• 12% reduction in all-cause mortality
• 11% lower hospitalization for heart failure
• 21% reduction in a composite kidney outcome

GLP-1 agonists reduce body weight, blood pressure, HbA_1c, and low-density lipoprotein cholesterol. These medications are recommended for the secondary prevention of cardiovascular disease in type 2 diabetes patients.⁴

Other diabetes drugs, including insulin, most dipeptidylpeptidase-4 (DPP4) inhibitors, sulfonylureas, appear to have neutral or positive impacts on cardiovascular health. However, saxagliptin and pioglitazone may be risky in patients with heart failure.⁴

Multidisciplinary Approach to Diabetes

Diabetes care is traditionally managed by primary care doctors, endocrinologists, nurses, and dietitians. However, casting a wider net for the care team can offer several benefits. Diabetes affects the whole body, impacting vision, kidney function, the cardiovascular system, nervous system, brain, and more.

Health professionals who not only treat these issues but can help prevent them are critical for the significant number of people living with diabetes and prediabetes. Given the well-established link between diabetes and heart health, cardiologists play an essential role in supporting diabetes patients. In addition, pharmacists, community health representatives, mental health providers, and other specialists like nephrologists and ophthalmologists are important players in the diabetes care team.

Earlier introduction of a multidisciplinary team may improve care and outcomes for diabetes patients. Rather than waiting for costly and debilitating complications, recognizing the risks and expanding the care team sooner can improve monitoring and behavior change, providing diabetes patients with a better quality of life.⁵