Combined Effects of Glycated Hemoglobin A1C and Blood Pressure on Carotid Artery Atherosclerosis in Nondiabetic Patients

Background: The relationship between HbA(1C), blood pressure, and carotid atherosclerosis in nondiabetic patients is not clear. Hypothesis: HbA(1C) and blood pressure can affect carotid-artery atherosclerosis in nondiabetic patients. Methods: This retrospective cross-sectional study included 216 patients without diabetes mellitus. A positive carotid ultrasonographic result was defined as intima-media thickness of the common carotid artery >= 0.9 mm, or presence of carotid plaque. Results: Compared with patients without carotid atherosclerosis, patients with carotid atherosclerosis had significantly higher levels of HbA(1C) and systolic blood pressure (SBP). Higher levels of HbA(1C) and SBP were found to be associated with increased carotid atherosclerosis. Given similar SBP levels, higher HbA(1C) (> 5.6%) was also related to increased carotid atherosclerosis. In multiple logistic regression analysis, HbA(1C) (odds ratio: 4.1, P = 0.009) emerged as the only statistically significant modifiable factor that was associated with carotid atherosclerosis, independent of smoking, body mass index, fasting plasma glucose, 2-hour plasma glucose, SBP, diastolic blood pressure, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Conclusions: Our study shows that a slight increase of HbA(1C) may associate with carotid atherosclerosis in nondiabetic patients. Moreover, the coexistence of an elevated SBP level and a slightly increased HbA(1C) level may have a more significant effect on carotid atherosclerosis.