Preventing Cardiovascular Disease in People with Diabetes

Cardiovascular disease (CVD), which includes heart attack and stroke, is the leading cause of death in the US today, accounting for nearly 40% of all deaths. Cardiologists have become increasingly skilled at treating people who’ve already had one heart attack or stroke in order to minimize their risk of a second one. This kind of treatment is called secondary prevention. Unfortunately, many patients don’t survive their first event, which is why it is best to treat individuals before they get their first. This is called primary prevention, and it’s particularly important for diabetic patients, who are at twice the risk of developing myocardial infarction (MI), or a heart attack, and stroke compared to the general population. Diabetes is itself a risk factor for CVD and up to 80% of type 2 diabetic patients eventually develop cardiovascular disease as a complication of diabetes.

In January, the American Heart Association and American Diabetes Association published a statement giving their joint recommendations for the primary prevention of CVD in patients with diabetes. Below we present an abbreviated version.

• Patients should be individually assessed for their CVD risk level, since not all diabetic patients are at the same risk for developing CVD. Our favorite risk calculator is the UKPDS Risk Engine.

• A healthy lifestyle is still the best way to avoid CVD. Overweight patients should strike for a long-term weight loss of five to seven percent through improved lifestyle. All patients should limit fat and total calories and increase physical activity – ideally to 150 min/week of moderate intensity aerobic activities or 90 min/week of vigorous intensity aerobic activities, spread over at least three days a week.

• Blood pressure control is important and should be measured at every routine diabetes appointment. Diabetic patients should have blood pressure below 130/80 mm Hg. The ADA and AHA recommend ACE inhibitors as the best drugs for controlling blood pressure. Other options include angiotensin receptor blockers.

• Lipid control is also important. Diabetic patients usually have low HDL (“good”) cholesterol and high (“bad”) LDL cholesterol and triglycerides. The ADA and AHA recommend annual lipid panel lab tests, except for patients under 40 with low-risk lipid values, in which case lipid tests can be done every two years (having low-risk lipid values means meeting the targets discussed below). Lifestyle modification should be the first step in improving lipid profiles, but statins can be very helpful for reducing LDL cholesterol. The recommended target levels are: LDL should be under 100 mg/dL, HDL should be over 40 mg/dL for men and over 50 mg/dL for women, and triglycerides should be under 150 mg/dL. Fibrates can be used to lower triglycerides and niacin can be used to increase HDL, though it’s not clear yet whether it is safe to combine statins with fibrates or niacin (a trial under way, called ACCORD, is studying this question).

• Some doctors recommend that all patients over 40 years of age with diabetes should take statins – although it’s not part of this piece, it is something we would definitely recommend asking your doctor about, since studies have shown that when diabetics who have completely normal cholesterol take statins, they have a lower incidence of heart attacks compared to other people with normal cholesterol who did not not take statins.

• All patients with diabetes should without a doubt stop smoking. Both smoking and diabetes are major risk factors for CVD. Part of the recommendation is actually that every tobacco user should be advised to quit.

• Aspirin is recommended for patients at increased risk of CVD. These include people who are over 40 years, have a family history of CVD, have hypertension, smoke, have high-risk lipid profiles, or albuminuria (a measure of kidney disease). This means that a very large number of type 2 patients should be taking aspirin.

• Of course, better glycemic control is critical for diabetic patients. Epidemiological studies including EDIC, the follow up to the landmark DCCT trial, have suggested that there is an 18% decrease in CVD risk for every 1% drop in A1c for type 2 patients. The ADA and AHA recommend a target A1c of less than 7% and as near to normal (under 6%) as possible without causing significant hypoglycemia.

The bottom line: If you have diabetes, you are at higher risk of developing cardiovascular disease. Make sure you know your CVD risk level, and that both you and your doctor are keeping tabs on your blood pressure, lipid levels, and glycemic control. If you are at high risk of developing CVD, you should probably be taking aspirin, and you should definitely not be smoking. While lifestyle management (exercise and diet) is the best way to avoid CVD, many drugs can also help you meet the ADA and AHA’s recommended goals for CVD prevention.

(Buse J. B. et al. “Primary Prevention of Cardiovascular Disease in People with Diabetes Mellitus: A Scientific Statement from the American Heart Association and American Diabetes Association.” Diabetes Care. Jan 2007. 30(1):162-172.)