Background: Diabetes and other forms of impaired glucose metabolism (IGM) can be present in patients with coronary artery disease (CAD), despite normal fasting glycemia and no prior evidence of diabetes. Undiagnosed IGM can be associated with increased risk of cardiovascular events.
Objective: To assess the prevalence of IGM in patients with CAD and without diabetes and to identify its repercussions on their cardiovascular risk profile.
Methods: Consecutive patients with CAD documented by angiography, without prior history of diabetes and fasting glycemia < 126 mg/dL, were studied. An oral glucose tolerance test (OGTT) was performed to identify and classify IGM. The patients were divided into three groups: normal if fasting glycemia < 100 mg/dL and normal OGTT; prediabetes if fasting glycemia > or = 100 mg/dL and abnormal OGTT, with 2-h glycemia > or = 140 and < 200 mg/dL; and diabetes if 2-h glycemia > or = 200 mg/dL after OGTT. For assessment of the cardiovascular risk profile, various clinical, laboratorial (including lipid profile, fasting insulinemia 2 h after OGTT, insulin resistance index and A1c hemoglobin) and angiographic characteristics were analyzed. The differences between groups were determined.
Results: 54 patients were studied (mean age 65 +/- 9 years, 78 % male) and IGM was identified in 37 (69%), with prediabetes in 23 (43%) and diabetes in 14 (26%). Patients with IGM had more dyslipidemia, higher levels of fasting glycemia, triglycerides and urea and lower HDL cholesterol. Metabolic syndrome was diagnosed in 12% of patients in the normal group, 44% in the prediabetes group and 50% in the diabetes group (p = 0.047). CAD was more severe in the presence of IGM, being multivessel in 84% of these patients versus 59% in the normal group (p = 0.046).
Conclusion: In patients with CAD without clinical suspicion of diabetes, a routine OGTT can identify a significant percentage with prediabetes and diabetes, which can have a negative impact on their cardiovascular risk profile.