Diabetes Mellitus: Coronary Heart Disease Equivalent

Marwan M. Refaat, MD, FACC, FAHA, FHRS, FASE, FESC, FACP
Assistant Professor of Medicine, AUBMC

Coronary heart disease (CHD) is caused by atherosclerosis, which is the gradual build-up of fatty deposits (plaques) in the coronary arteries. Over time, the deposits narrow the coronary arteries causing reduced blood flow to the heart and chest pain (angina). Ultimately, the artery may become blocked, leading to heart attack and sudden death.

Diabetes has an adverse effect on the blood vessels, making them more likely to become blocked if plaque forms. In addition, it causes the blood to clot more easily, further increasing the likelihood of blockage. Diabetics develop atherosclerosis at a younger age and more severely than non-diabetics. The prevalence of CHD rises from 2% to 4% in the general population to as high as 55% among adult diabetic patients. Heart disease, particularly CHD, is the leading cause of diabetes-related mortality among patients with diabetes mellitus as sudden cardiac death being 50% more frequent in diabetic men and 300% more frequent in diabetic women compared to non-diabetics.

Increasing blood sugar levels and glycosylated hemoglobin concentrations (HbA1c) predict cardiovascular mortality in type 2 diabetes; each 1% reduction of glycosylated hemoglobin would be associated with a 14% reduction in myocardial infarction (heart muscle damage).

Numerous factors including hyperglycemia (high blood sugar levels), hyperlipidemia (high cholesterol levels), hypertension (high blood pressure) and smoking, contribute to the process of accelerated atherosclerosis in diabetes. Screening for CHD might be indicated in younger individuals, with a relatively short duration of DM and few risk or diabetic complications, because an early and effective more aggressive management of these risk factors is recommended in the presence of CHD.

Given the high risk in patients with diabetes, it is a major challenge to restore the well-being and quality of life and prevent vessel disease. Reduction of the increased risk requires a multifactorial approach that can be achieved by intensive blood sugar level control and aggressive treatment of other cardiovascular risk factors. Lipid lowering therapy is recommended for diabetics over 40 years of age or patients less than 40 years of age with additional risk factors targeting LDL-C (bad cholesterol) <100 mg/dl. High blood pressure is associated with increased cardiovascular event rates and mortality in persons with diabetes. Diabetics should be encouraged to undertake moderate exercise, such as walking, jogging, swimming and cycling. Current recommendations suggest brisk walking or its equivalent for 30-45 minutes on most days, and ideally every day.

In Diabetic patients with documented CHD, over 90 percent of ischemic episodes (heart attacks) were without symptoms!!

It is important to note that in diabetics, there is blunted appreciation of chest pain, often resulting in silent ischemia or even silent infarction (muscular damage). Diabetics are advised not to ignore or disregard any cardiac symptoms and medical help should be sought for CHD screening and better risk reduction.

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