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Complications of Diabetes Mellitus: Overview and Cardiac Complications

Diabetes mellitus can be controlled by diet, exercise, and medications, as needed. When it is not well controlled, it affects many parts of the body, particularly the heart, eyes, kidneys, and nerves. In addition, birth complications occur more often in infants born to women with poorly controlled diabetes.

Prevention of complications depends on control of blood sugar and managing the major risk factors for heart disease, such as smoking, blood pressure, and high cholesterol. Diet plays an important role, along with exercise and appropriate medications.

Cardiac Complications

Cardiovascular disease is the leading cause of death in individuals with diabetes. Control of cardiac risk factors is therefore essential.

Risk Factors


  • Regular check–ups, including a physical examination and blood testing, are recommended for all individuals with diabetes. Further, an EKG or cardiac stress testing may be appropriate for some patients.
  • Blood pressure control is particularly important. The goal blood pressure should be less than 130/80 millimeters of mercury (mmHg), and further lowering may be beneficial.
  • The goals for blood cholesterol levels are somewhat different for people with diabetes than for the general population. Low density lipoprotein (also called LDL, or “bad” cholesterol) should be less than 100 milligrams per deciliter (mg/dl), or 2.6 millimoles per liter (mmol/L), in the measuring system used outside the U.S. In certain patients (especially those with known heart disease), the goal may be less than 70 mg/dl (1.8 mmol/L). Triglycerides (particles of fat in the bloodstream) should be less than 150 mg/dl, and high density lipoproteins (HDL or “good” cholesterol) should be greater than 45 mg/dl (1.2 mmol/L) for men and greater than 55 mg/dl (1.4 mmol/L) for women.


Dietary and behavioral modifications, including smoking cessation and loss of excess weight, are important for the prevention and management of cardiac complications. When further therapy is needed, specific medicines may be helpful.

  • An aspirin a day is recommended for most persons older than 30, particularly in those who have additional cardiovascular risk factors. Potential side effects must be considered, including ulcers and bleeding.
  • Hypertension in diabetes patients should be treated with an angiotensin–converting enzyme (ACE) inhibitor (e.g., lisinopril) or angiotensin receptor blocker (e.g., losartan). Further drugs to lower blood pressure may be required, including diuretics, beta blockers, and calcium channel blockers
  • Cholesterol–lowering medications, such as statins, are likely to be effective in reducing cardiovascular risk.

Nutritional Considerations
To reduce the risk of cardiac complications, the appropriate dietary changes are those that improve cholesterol levels, reduce blood pressure, and control blood sugar. These steps are discussed in detail in the chapters on coronary heart disease, hyperlipidemia, hypertension, and diabetes. Here are two important nutritional considerations:

  • A substantial body of evidence suggests that a combination of a vegetarian diet, regular exercise, smoking cessation, and stress management yields greater improvements in cardiovascular disease, compared with other regimens.

    The Multicenter Lifestyle Demonstration Project, which included 440 patients with coronary artery disease, of whom 91 also had diabetes, showed that such a regimen benefits those with diabetes about the same as it benefits those without diabetes. In a randomized, controlled trial of individuals with type 2 diabetes, a low–fat vegan diet reduced LDL cholesterol by 21 percent and reduced triglycerides by 16 percent among participants. These changes were particularly remarkable in that many of the study participants were already receiving cholesterol–lowering medications, yet the diet led to substantial further improvements.

    The type of carbohydrate in the diet may be important. Diets high in refined carbohydrates and “simple” sugars may increase triglyceride levels for some individuals, but high–carbohydrate diets that are drawn from high–fiber and complex carbohydrate foods–beans, starchy vegetables, and whole grains–appear to have the opposite result.
  • A randomized controlled clinical trial of alpha–lipoic acid supplementation, administered at 800 mg/day for four months, showed improvements in heart and nerve function. However, further study with a larger number of individuals is required to assess whether these initial findings bear out.


Complications of Diabetes Mellitus: Eye Complications >>