Background: Homocysteine​​ is an amino acid that is produced during the metabolism of the methionine cycle. In previous studies, a causal role of homocysteine in coronary artery disease (CAD) has been investigated; however, the homocysteine ​​level in diabetic and non-diabetic patients with CAD has not been compared. This study aimed to investigate this issue.

Materials and Methods: This cross-sectional study was conducted on 200 patients with CAD in Kashan Shahid Beheshti Hospital during 2014-2015. Coronary artery disease was confirmed by angiography. Homocysteine levels, blood urea nitrogen, creatinine, hemoglobin A1C and mean blood pressure were measured. Data were analyzed using t-test with SPSS version 16.

Results: In this study, one hundred and eight of patients (54%) were men. The mean concentrations of hemoglobin A1C in diabetic and non-diabetic patients were 6.69±1.44 and 5.74±0.92, respectively (P<0.001). Moreover, the mean homocysteine serum ​​levels in diabetic and non-diabetic patients were 19.89±6.86 &mu;mol/L and 24.35±9.93 &mu;mol/L, respectively (P<0.001).

Conclusion: Results of the current study showed that the homocysteine serum level ​​in patients with CAD was higher than the normal level and in patients without diabetes was significantly higher than patients with diabetes.​​ Also, in diabetic patients with CAD, the serum creatinine and urine protein levels were higher than those in non-diabetics patients.