Insulin resistance is believed to be the initial defect leading to glucose intolerance. Together with hyperin-sulinemia, it is an independent predictor of cardiovascular disease. The Framingham study was the first epidemiological study to demonstrate an increased risk of congestive heart failure in diabetes mellitus. Subsequent studies have confirmed that glucose abnormalities and congestive heart failure are closely interrelated. In the Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) study, glucose metabolism was abnormal in 43% of the patients. Diabetes is an independent risk factor for the development of congestive heart failure. Heart failure has a significandy worse prognosis with vs without diabetes. The main causes of this generally dismal prognosis include the poor outcome of myocardial infarction, the severity and distribution of coronary artery disease, abnormal autonomic function, and the possible existence of a specific diabetic cardiomyopathy.
Diabetes and ischemic heart disease
Type 2 diabetes, including the prediabetic period, is an important risk factor for atherosclerosis, which accounts
for up to 60% of all diabetes-related deaths. Proper treatment, including meticulous metabolic control, considerably improves prognosis in diabetics with myocardial infarction and may also prevent its occurrence. Diabetics have a higher incidence of heart failure and increased mortality after acute myocardial infarction than nondiabetics. In the Diabetes Mellitus insulin-Glucose Infusion in Acute Myocardial Infarction (DIGAMI) study, heart failure was the most common cause of morbidity and mortality, accounting for 66% of total mortality during the first year of follow-up. Diabetics requiring coronary angioplasty or bypass procedure have a worse prognosis than nondiabetics, with a higher risk of restenosis after coronary angioplasty and of myocardial injury after any of these interventions.
Diabetic cardiomyopathy (diabetes-related myocardial dysfunction) is characterized by a lack of compensatory response to myocardial ischemia or injury and includes early impairment of diastolic function. This suggests that interventions against hyperglycemia and increased free fatty acid oxidation may be beneficial.