To review population-based studies that investigated the association and nature of association between glycemic control and the risk for coronary heart disease in patients with non–insulin-dependent diabetes mellitus (NIDDM).

Study 1 included 133 newly diagnosed patients with NIDDM from eastern Finland, who were 45 to 64 years of age at baseline. These patients were followed up to 10 years for cardiovascular mortality. Study 2 included 229 newly or previously diagnosed patients with NIDDM from eastern Finland, aged 65 to 74 years at baseline. These patients were followed up to 3.5 years for coronary heart disease mortality and all coronary heart disease events (mortality or nonfatal myocardial infarction).

Prospective, population-based studies that included indicators of glycemic control and the evaluation of coronary heart disease and cardiovascular risk.

Study 1: 10-year cardiovascular mortality was significantly and linearly associated with glycemic control (fasting blood glucose and glycated hemoglobin A₁ levels) independently of the mode of treatment. A high fasting blood glucose level significantly predicted cardiovascular mortality in multiple logistic regression analysis independently of other risk factors. Study 2: Glycated hemoglobin A_1c was the most important single risk factor associated with coronary heart disease death or all coronary heart disease events. In multiple logistic regression analysis, glycated hemoglobin A_1c was significantly associated with coronary heart disease death after adjustment for other cardiovascular risk factors.

Two prospective, population-based studies from Finland give evidence for the linear association of glycemic control with the risk for coronary heart disease in middle-aged and elderly patients with NIDDM.