Cardiac Risk Factor: Diabetes

Diabetes is a real villain in the tragic human drama of coronary artery disease by convincingly masquerading its symptoms to confuse and mislead every one of the other players, even the director.

Diabetes is a disease of antiquity. The National Diabetes Data Group defines diabetes as a fasting blood sugar of 140 mg/dl or above. Over the past three decades, our diabetic population has quadrupled to about 25 million, approximately 10% of the adult American population. Of these, about 90% are adult-onset type and 10% are juvenile-onset type. Except for some pancreatic disease or injury, diabetes has a very strong genetic predisposition. The disease has an insidious onset with steady progress to permanent atherosclerosis (premature aging of the vascular system) with a predilection for heart, eyes and kidneys.

Degenerative changes of nerve fibers in diabetics constitute the right setting for painless heart attacks in these patients. In diabetics, a heart attack may present as sweating, weakness, shortness of breath, nausea or vomiting. An ill-informed patient often discounts these symptoms as “stomach flu” or “bronchitis.”

Painless heart attack is more of a norm in diabetics rather than the rule.

In the U.S. alone, 77,000 diabetics die each year from cardiovascular diseases (CAD, hypertension, and stroke) and its complications. Atherosclerosis and its complications account for 75% of mortality among diabetics.

In fact, 25% of all heart attacks in the United States occur in patients with diabetes. Diabetics in general have a poor outcome in surviving an acute myocardial infarction. They also have increased graft occlusion rate after bypass graft surgery, and a more than average reocclusion rate following coronary angioplasty. About 50% of our adult onset diabetics are unidentified or not treated with specific medications. It is ideal to check the whole population for prevalence of diabetes, in the absence of which, individuals with a high predisposition for diabetes must be identified. They are: 1) relatives of known diabetics, 2) people with overweight, 3) mothers delivered of large babies, 4) older age group.

About 50% of our adult-onset diabetics are unidentified or not treated with specific medications.

Since the invention of insulin in 1921, the management of diabetes has been revolutionized. Yet diabetes continues to be a major medical problem and consumes 15% of our total healthcare dollars. As the age of the U.S. population continues to increase along with the incidence of obesity, we can expect a dramatic increase of diabetes-related cardiovascular disease in the U.S.

Once you diagnose diabetes in a patient, you are about to touch the tip of an iceberg of a myriad of other problems. Diabetes almost never presents as an isolated problem in a person. There is a very high prevalence (more than 66%) of other risk factors like obesity, hypertension, and hyperlipidemia.

Diabetics have an abnormal and aggressive inflammatory response to atherosclerosis or to other common viral or bacterial infections.

Diabetes has an abundance of other non traditional risk factors and serum markers for coronary artery disease, such as:

• High waist-to-hip ratio (Apple belly)
• High fibrinogen level
• High level of leukocyte count
• High levels of plasminogen activator inhibitor
• High levels of homocysteine
• High levels of C-reactive protein
• High Lp(a)
• Low serum albumin levels
• Microalbuminemia
• High levels of Factor VIII
• High levels of von Willebrand’s factor
• Low magnesium

Based on this information, our strategy is to strive for absolute glycemic control with appropriate therapeutic agents. Lipid management with statin certainly reduces the markers of inflammation and the incidence of acute coronary syndrome. In a hyperlipidemic diabetic, the use of fibrates deserves special attention due to its effect to reduce fibrinogen. The beneficial effects of weight reduction, exercise, and smoking cessation are exceptionally useful in these patients.

The various nonspecific risk factors listed above suggest that diabetics have an abnormal and aggressive inflammatory response to atherosclerosis, or to other common viral or bacterial infections. This nonspecific inflammatory process, irrespective of its cause, leads to excessive expression of C-reactive proteins, cytokine tumor necrosis factor Alpha and fibrinogen resulting in a chain of vascular events leading to plaque rupture, hemorrhage, and thrombosis – the common denominators of acute coronary syndrome.

An aspirin a day certainly has a significant role in the primary prevention of AMI (30%) in the general population. However, the benefit is even higher in diabetics due to their abnormal inflammatory response of the vascular endothelium.