Diabetes and Coronary Heart Disease

Abstract

Abstract. Clinically manifest coronary heart disease (CHD) is not uncommon in diabetics with insulin-dependent type of the disease below the age of 40, particularly when the duration of diabetes is long. Clinically manifest CHD is very common in diabetics with maturity-onset, non-insulin-dependent type of the disease, and in this type of diabetes the frequency of CHD shows little or no relation to the duration of diabetes. Premenopausal female diabetics have a clinically manifest CHD almost as often as male diabetics of the same age - a situation in sharp contrast to that in non-diabetics with large excess of CHD in males. The incidence of all manifestations of CHD (sudden and non-sudden CHD death, non-fatal myocardial infarction, »silent« myocardial infarction, and angina pectoris) is increased in diabetics as compared to non-diabetics, but the excess of CHD mortality in diabetics is especially marked, being 3 to 4 times higher than in non-diabetics. The incidence of congestive heart failure is markedly increased in diabetics and this is in part independent of increased occurrence of CHD and hypertension among diabetics. Subclinical abnormalities of left ventricular function are common in diabetics and these abnormalities appear to show some relationship to the metabolic control of diabetes and in insulin-dependent diabetics also to the presence of microangiopathy. Diabetes is associated with changes in general CHD risk factors to atherogenic direction. These changes include abnormalities in the levels and composition of plasma lipids and lipoproteins and increased frequency of hypertension. The impact of general risk factors on CHD risk appears to be similar in diabetics and non-diabetics. The major part of the excess CHD in diabetics, however, is not explained by the effect of diabetes on general cardiovascular risk factors, but is due to an independent effect of diabetes itself through mechanisms which are far from solved.