Impact of Diabetes on Homocysteine Levels and Its Relationship with Coronary Artery Disease: A Single-Centre Cohort Study

Background/Aims: Coronary artery disease (CAD) is a major cause of mortality worldwide. Hyperhomocysteinemia has been identified as a risk factor for CAD due to increased thrombogenicity, oxidative stress status and endothelial dysfunction. Few data have been provided on the impact of diabetes on homocysteine and its relationship with the prevalence and extent of CAD in this high-risk subset of patients and therefore, this is the aim of this study. Methods: Our population is represented by a consecutive cohort of patients undergoing coronary angiography at Azienda Ospedaliera-Universitaria, ‘Maggiore della Carità', Novara, Italy from March 2007 to October 2012. Results: Diabetes was observed in a total of 1,125 out of 3,534 patients. Diabetes was associated with more advanced age, hypercholesterolemia, arterial hypertension, renal failure, previous myocardial infarction, coronary revascularization (p < 0.001, respectively) and smoking (p = 0.001). Patients with diabetes were more frequently on angiotensin-converting-enzyme inhibitors, angiotensin receptor blockers, beta-blockers, calcium-antagonists, diuretics, statins (p < 0.001, respectively), and acetylsalicylic acid (p = 0.004). Patients with diabetes displayed higher creatinine and triglycerides (p < 0.001), but lower total and high-density lipoprotein-cholesterol (p < 0.001) and haemoglobin (p < 0.001). Diabetes was associated with a significantly higher prevalence and extent of CAD and more complex lesions at angiography, including calcified lesion, total occlusions, in-stent restenosis. No significant difference was found in total homocysteine (tHcy) levels between diabetic and non-diabetic patients (p = 0.2). No difference in the percentage of patients with tHcy above the third tertile (≥18.2 nmol/ml) was observed between patients with or without diabetes (32.8 vs. 35%, p = 0.18; adjusted OR 0.88, 95% CI 0.73-1.05, p = 0.14). Among patients with diabetes, no significant association was found between tHcy, CAD (82.4 vs. 83.6 vs. 78.6%, p = 0.19) or severe CAD (33.2 vs. 33.1 vs. 36.9%, p = 0.18). Same results were observed after correction for baseline differences (adjusted OR 0.78, 95% CI 0.61-1.02, p = 0.11) for CAD and severe CAD (adjusted OR 0.92, 95% CI 0.76-1.13, p = 0.46). Conclusions: In our study, diabetes was not associated with higher tHcy levels. Furthermore, elevated tHcy is not a risk factor for CAD among patients with diabetes.