Early recognition and treatment of glucose abnormalities to prevent type 2 diabetes mellitus and coronary heart disease.

Striking parallels exist in both risk and protective factors between coronary heart disease and type 2 diabetes mellitus. Patients with insulin resistance are more likely to develop diabetes and coronary heart disease. Better treatment of diabetes may result in less coronary heart disease, although this has not yet been established. Reliance on fasting glucose determinations alone will overlook a substantial number of patients at risk for diabetes and subsequent coronary heart disease. Measurement of glycosylated hemoglobin should be a routine part of screening for patients at risk for diabetes. Patients with glycosylated hemoglobin levels in the high-normal range should be treated more aggressively with diet, exercise, and medication because evidence is good that diabetes can be prevented (or its onset delayed). Patients with borderline elevations of low-density lipoprotein cholesterol concentrations and with high-normal glycosylated hemoglobin levels should be considered for statin therapy, and patients with hypertension with high-normal glycosylated hemoglobin levels should be treated with angiotensin-converting enzyme inhibitors as first-line agents. Studies to determine whether metformin is useful in this population are ongoing.