“The No. 1 consequence of diabetes is cardiovascular disease,” says Scott M. Grundy, M.D., Ph.D., lead author of the executive summary and chair of the American Heart Association’s diabetes committee. “About two-thirds of people with diabetes eventually die of heart or blood vessel disease. We want to make people more aware of the problem of diabetes as a major contributor to the problem of cardiovascular disease.”
Several recent studies show that the increase in cardiovascular disease (CVD) risk associated with diabetes can be lessened by controlling individual risk factors such as obesity, high cholesterol, and high blood pressure.
Losing weight can have a great impact on a dangerous pre-diabetic condition called the metabolic syndrome, says Grundy, who is also a professor of internal medicine at the University of Texas Southwestern Medical School in Dallas. The metabolic syndrome is a prediabetic state characterized by abdominal fat, low-levels of high-density lipoprotein, high levels of triglycerides and high blood pressure.
“One-third to one-half of the people with this syndrome eventually develop diabetes, but metabolic syndrome can lead to cardiovascular disease even before you get diabetes because of the high blood lipids and cluster of risk factors,” he says.
“The syndrome is particularly alarming in adolescents. It is a multi-tiered problem that starts with obesity and continues to the metabolic syndrome and diabetes,” Grundy explains. “Changes that are spread out in most adults who gain weight over many years are compressed into a few short years in young teens.”
The rise in type 2 diabetes in children and adolescents is a disturbing trend, the authors say. It is likely due to obesity and sedentary lifestyle, and increases their risk of early CVD.
Grundy says that merely calling diabetes a risk factor underestimates its effect on cardiovascular disease because the consequences are so far-ranging—from heart attack and stroke to kidney disease, heart failure, diminished heart function and problems in both the large and small vessels, like those in the eyes.
There are two forms of diabetes. Type 1 diabetes results from a failure to produce insulin, and it most often begins in childhood or adolescence. It accounts for 10 to 15 percent of all diabetes. Much more common is type 2 diabetes, which results from insufficient production of insulin, poor response to insulin (insulin resistance) or both. People with type 2 diabetes often have other risk factors for CVD too, such as high cholesterol and obesity. Type 2 diabetes is usually brought on by obesity, but susceptibility to it varies considerably in the population.
“In the last few years we’ve learned how important it is to treat cardiovascular risk factors in patients with diabetes and how much benefit can be derived,” says Grundy.
With many other ailments, there are a lot of treatments or aspects of disease management that patients can do on their own, he says. However, diabetes is one condition in which physician involvement is critical.
“It is extremely important that patients with diabetes work closely with physicians to reduce risk factors and not try to self-manage their condition,” he says. “Diabetes is a serious and complicated condition that must be treated with a team approach between the patient and physicians, which may include a primary care doctor, an endocrinologist and a cardiologist.”
More than 16 million Americans have diabetes and approximately one-third of them are undiagnosed and untreated. Blacks and Hispanic Americans have nearly twice the incidence of type 2 diabetes as whites and many Native American tribes are experiencing epidemic rates.
The age-adjusted prevalence of diabetes has risen dramatically from 2.6 percent of adults over age 45 in 1960 to 7 percent in 1990, and it is still rising. Overweight and obesity are important contributors to this trend.
Almost 35 million Americans (20 percent of middle-aged adults and 35 percent of those over age 65) have some degree of abnormal blood sugar metabolism, a condition that can lead to diabetes and poses an increased risk of CVD and premature death, according report.
Rita Redberg, M.D., M.Sc., a member of the writing group and an associate professor of medicine at the University of California-San Francisco, says people with diabetes should be considered at high risk for CVD and their risk factors should be treated aggressively simply because of their diabetic status.
A person’s risk for CVD can be obtained inexpensively and non-invasively, she adds, citing the Framingham risk score as the “gold standard” for CVD risk assessment. It requires only a doctor’s office visit to assess blood pressure, weight, smoking status and a blood sample to check cholesterol levels.
Highlights from the American Heart Association’s
Prevention Conference VI:
Diabetes and Cardiovascular Disease
For physicians and patients:
- Office-based risk factor evaluation is mandatory in people with diabetes, and aggressive risk factor modification should be based on those results.
- The metabolic syndrome commonly precedes the onset of diabetes by several years. Insulin resistance apparently predates the risk factors associated with the metabolic syndrome, thus detection of insulin resistance relatively early in life offers the opportunity to identify at an early stage those people likely to develop blood fat abnormalities, HBP and ultimately diabetes.
- A person with diabetes who smokes is at double the risk for cardiovascular disease. Therefore, every effort must be made to convince the patient to stop smoking.
- High blood pressure (HBP) increases a diabetic patients’ risk of coronary heart disease (CHD), stroke, kidney failure and heart failure. Treatment of HBP in people with diabetes should be intensive enough to reach blood pressure goals.
- The common drugs used to treat high blood pressure—diuretics, beta-blockers, angiotensin converting enzyme (ACE) inhibitors and calcium channel blockers—are generally effective in treating patients with diabetes.
- Assiduous treatment of high blood pressure in people with diabetes can delay the progression of diabetic nephropathy and retinopathy as well as CVD.
- Diabetes is marked by two lipid disorders that must be addressed: higher than optimal levels of low-density lipoprotein (LDL) and a triad of blood fat abnormalities marked by elevated triglycerides, small, dense LDL and low levels of high-density lipoprotein (HDL), the protein carrier that is thought to help protect the arteries.
- The blood of patients with insulin resistance and type 2 diabetes is more likely to form artery-blocking clots. Chronic aspirin therapy is the most readily available way to counteract this tendency.
- Control of the high glucose levels in the blood is mandatory in order to prevent disease in the fine microvessels, such as those in the eyes and kidneys. There are several drugs available to reduce blood sugar levels, and the action of these drugs can be enhanced by weight loss and physical activity. If introduced early enough, these lifestyle changes may delay the need for drugs for many years.
- Preliminary but growing evidence shows that aggressive glucose lowering during acute CVD events and procedures is beneficial.
- Body weight, body mass index and waist circumference should be measured and monitored while managing patients with diabetes.
- Weight management requires a team approach that includes physicians, nurses, dietitians, or other health professionals and pharmacists.
- Any weight loss is beneficial to the patient, but diets that achieve rapid weight loss are generally unsuccessful because weight that is quickly lost tends to be quickly regained.
- Slow weight reduction with a goal of losing 10 percent of body weight over one year is more likely to produce long-term success.
- Physical inactivity contributes to overweight, impairs insulin sensitivity and worsens the metabolic syndrome.
- In patients who are well enough to exercise, the goal should be a minimum of 30 minutes per day of moderate-intensity exercise such as brisk walking. If more intense exercise can be tolerated without harm, it will provide an even greater benefit.
- Despite widespread agreement that most people with type 2 diabetes need to lose weight, there is much debate over the most desirable diet to accomplish that goal with the pendulum swinging back and forth between low-fat and low-carbohydrate diets.
- Most investigators agree that diet for people with diabetes should be low in saturated fatty acids and cholesterol to keep LDL cholesterol levels down.
- The American Diabetes Association (ADA) notes that there is no “diabetic diet” but the ADA offers a series of principals that should be followed, which include reduced protein intake in those with diabetic kidney disease. In addition, the ADA discourages high intakes of fructose because of a possible adverse effect on diabetic dyslipidemia.
The reports make the following organizational recommendations:
- The American Heart Association (AHA) and ADA should coordinate their efforts to develop a joint position statement on prevention of CVD in patients with diabetes that would include prevention and therapy goals for each CVD risk factor.
- The AHA and ADA should promote improved treatment of lipid disorders in patients with diabetes. Guidance is needed on the use of lipid-lowering drugs in combination.
- The AHA and ADA should review and coordinate their recommendations for chronic aspirin use in patients with diabetes but without CHD.
- Develop and evaluate programs to ensure that every person with newly diagnosed diabetes has aggressive control of all CVD risk factors.
- Develop effective programs to ensure that every patient with diabetes, regardless of ethnicity and economic status, receives adequate preventive therapies aimed at smoking cessation, cholesterol and triglyceride correction, blood pressure lowering, and blood glucose level reduction.
- Encourage clinical trials to determine the optimal timing of revascularization in the patients with diabetes.
- Encourage clinical trials to specify an adequate number of people with diabetes to allow subgroup analysis.
- Conduct educational programs for doctors and healthcare providers that emphasize current evidence and guidelines regarding revascularization strategies in people with diabetes.
CONTACT: For journal copies only,
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For other information, call:
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Editor’s Note: The American Heart Association’s program The Heart of Diabetes: Understanding Insulin Resistance is a no-cost 12-month program designed to educate people about the association between cardiovascular disease, diabetes and insulin resistance. People with type 2 diabetes are encouraged to control their heart disease risk through physical activity, nutrition and cholesterol management. To register for the program, call 1-800-AHA-USA1 or visit www.americanheart.org/diabetes.