Analysis of the Relationship of Glycated Hemoglobin with Subclinical Atherosclerosis and Arterial Stiffness in Non-Diabetic Patients: A Retrospective Study

Background: Cardiometabolic diseases present a major challenge to contemporary public health. Diabetes mellitus (DM) is widely recognized as a strong cardiovascular risk factor. However, the utility of glycated hemoglobin percentage (HbA1c) for assessing cardiovascular health in individuals without DM remains uncertain. This study examines the association between HbA1c levels and both the presence and severity of subclinical atherosclerosis and arterial stiffness in non-diabetic individuals. Methods: A retrospective analysis was conducted on the data from 59 patients (72.88% female; mean age: 54.82 ± 17.34 years) who exhibited no signs of acute illness or exacerbation of chronic diseases. All patients were hospitalized in the Department of Internal Medicine, Angiology and Physical Medicine at the Medical University of Silesia in Katowice, Poland, between June 2022 and May 2024. HbA1c level determination, central blood pressure measurement with pulse wave analysis (PWA), carotid–femoral pulse wave velocity (cfPWV) measurement, and Doppler ultrasound of the carotid arteries and lower extremity arteries measuring the intima–media thickness (IMT) in the common carotid arteries (cIMT), common femoral arteries (cfIMT), and superficial femoral arteries (sfIMT) were performed. Spearman’s rank correlation test was applied for statistical analysis. Subsequently, a multivariate analysis model was constructed, adjusting for age, sex, body mass index (BMI), and smoking. Results: Among the assessed parameters, the strongest positive correlations were found between HbA1c and parameters such as cIMT (R = 0.532; p < 0.001), cfIMT (R = 0.63; p < 0.001), sfIMT (R = 0.539; p < 0.001), and cfPWV (R = 0.504; p < 0.001). In the multivariate analysis model, a significant relationship was found only between HbA1c and augmentation index normalized to a heart rate of 75 per minute (AIx75) (β = −0.286; 95% CI: −0.566, −0.006; p = 0.045). Conclusions: In summary, although HbA1c correlates with some parameters related to arterial stiffness and subclinical atherosclerosis in non-diabetic patients, most observed relationships are explained by confounding variables.