Glycemic Management in Patients With Coronary Artery Disease and Prediabetes or Type 2 Diabetes Mellitus

A 67-year-old man presents for ongoing management of his cardiometabolic health. He has had type 2 diabetes mellitus (T2DM) for 7 years, hypertension, and dyslipidemia; is overweight; and suffered an inferior myocardial infarction 2 years earlier. Under your advice, he has made attempts to exercise with 30 minutes of daily walking and has tried to make healthy dietary choices and to watch food portion sizes. Over the past year, he lost 7 kg but regained 4 kg and remains overweight. His medications include metformin, a statin, an angiotensin-converting enzyme inhibitor, a β-blocker, and low-dose aspirin. On examination, his weight is 91.5 kg, body mass index is 32.0 kg/m2, waist circumference is 105.3 cm, and blood pressure 138/84 mm Hg. The rest of the examination is unremarkable and shows no evidence of microvascular complications of diabetes mellitus. His fasting plasma glucose is 10.3 mmol/L (185 mg/dL) and hemoglobin A1c (HbA1c) is 7.9%. Atherosclerosis is the principal cause of death and disability in patients with T2DM. In these patients, cardiovascular disease typically occurs at an early age, with great severity and diffuse distribution. More than half of the patients with newly diagnosed T2DM have established coronary artery disease, whereas one third of patients with coronary artery disease have known diabetes mellitus. Screening patients with established coronary artery disease but without preexisting diabetes will confirm the diagnosis of diabetes mellitus in an additional 15% to 20%. Impaired fasting glucose or impaired glucose tolerance will be detected in an additional 30% to 40%. Thus, more patients with established heart disease have abnormal than normal glucose tolerance, and screening for diabetes mellitus is warranted in patients with coronary artery disease or risk factors for cardiovascular disease. There are now multiple accepted ways to screen for diabetes mellitus in adults, including measurement …