Diabetes and heart disease
Diabetes is an independent risk factor for the development of coronary artery disease. The overall prevalence of coronary artery disease (IHD) is as high as 55% among adult patients with diabetes compared with 2-4% for general population without diabetes. Coronary heart disease is not only more prevalent, it is also clearly more extensive in diabetic than no diabetic patients.
Epidemiological data derived from the Framingham Heart Study demonstrated the increased incidence of heart attack in patients with diabetes and their poor outcome. The death rate from heart attack is more than double in men and more than quadruple in women who have diabetes, compared with the rate in their no diabetic counterparts. The relative risk of myocardial infarction (heart attack) is 50% greater in diabetic men and 150% greater in diabetic women. Similarly diabetic men succumb to sudden death 50% more often and diabetic women 300% more often than do their age-matched no diabetic counterparts. Diabetic women have poorer prognosis than do diabetic men and the cause is unknown. Acute myocardial infarction (heart attack) is said to account for as many as 30% of all deaths in diabetic patients.
Diabetes can predispose you to increased risk of heart attack for few reasons:
1. Patients with diabetes have higher levels of VLDL (bad cholesterol) and triglycerides (fatty substance) and lower level of HDL (good cholesterol) than do patients without diabetes. Elevated fat level in blood induces coronary artery damage and cause thrombosis at any time.
2. Blood cells, platelets aggregate spontaneously in patients with diabetes and form colt/thrombus inside coronary artery and cause heart attack.
3. The blood of patients with diabetes appear much thicker (high viscosity) than normal and solidify easily causing coronary block.
4. Autonomic neuropathy (nerve destruction by longstanding diabetes) may increase heart muscle oxygen demand and may reduce blood flow to heart muscle by causing increased vascular tone (contraction of the coronary artery).
Diabetic patients are at increased risk of complication associated with heart attack. Patients may fail to recognize the chest pain due to nerve damage. Diabetic patient may have heart attack without any chest pain and presentation may be atypical. Atypical symptoms like confusion, breathlessness, fatigue, vomiting may be the initial symptoms of heart attack. Patients may think that they are having these symptoms for their poor diabetic control like hypoglycaemia (low blood sugar) or due to hyperglycaemia (high blood sugar), which may cause delay in initiation of treatment of heart attack. For these false beliefs 35% of diabetic patients with heart attack were admitted in general wards rather than to the coronary care unit. Atypical symptoms may alter the patient’s perception of the nature of their illness and interfere with their decision to seek medical care and may cause unfortunate fatality.
Type 2 diabetes increases the risk of coronary heart disease by a factor of two to four. The relative increase in the rate of coronary heart disease among patients with diabetes in most studies is greater for women than men.
