Hyperhomocysteinemia in poorly controlled type 2 diabetes patients

Elevated blood level of homocysteine is strongly related to an increased risk for atherosclerosis and cardiovascular disease. The role of homocysteine in Type 2 diabetes vascular complications remains unclear. Our objective was to investigate homocysteine levels in poorly controlled Type 2 diabetic patients, who are at increased risk of vascular complications development. Forty-four Type 2 diabetic patients with no symptoms of any cardiovascular disease were divided into 2 groups: 26 patients with poor metabolic control treated with oral agents (aged 66.8 +/- 5.4 yr, diabetes duration 11.9 +/- 4.1 yr, fasting plasma glucose 13.9 +/- 4.6 mmol/l, HbA1C 9.8 +/- 1.6%), 18 well-matched diabetic patients well-controlled with oral agents (aged 65.8 +/- 4.7 yr, diabetes duration 10.9 +/- 4.2 yr, fasting plasma glucose 7.3 +/- 2.4 mmol/l, HbA1c 6.6 +/- 0.7%). The controls were 12 healthy subjects. Fasting total plasma homocysteine and plasma insulin concentrations were measured. Plasma total homocysteine concentrations were significantly higher in poorly controlled than in well-controlled diabetic patients and controls (17.1 +/- 4.5 vs 8.2 +/- 3.9 and 6.5 +/- 4.9 micromol/l respectively, p < 0.001). Insulinemia showed an inverse correlation with homocysteine levels (8.3 +/- 5.2 vs 14.6 +/- 5.2 and 9.3 +/- 6.1 microlU/ml, p < 0.001; r = -0.32, p < 0.05). HbA1c values correlated positively with homocysteine concentrations in poorly controlled subjects (r = 0.41; p < 0.05). In conclusion, chronic poor metabolic control of Type 2 diabetes is characterized by elevation of plasma homocysteine concentration, which also inversely correlates with endogenous insulin levels. These results may add to the understanding of the increased frequency and mechanisms of vascular damage in diabetes mellitus.