607-P: Hyperhomocysteinemia Is Closely Associated with Macular Edema in Type 2 Diabetes

Macular edema that impairs central vision is one of leading causes of blindness related to diabetes. Hyperhomocysteinemia is more common in type 2 diabetes, which may damage endothelium by excessive sulphation of connective tissues. In this study, we for the first time explored the relation of plasma total homocysteine concentration to diabetic macular edema in patients with type 2 diabetes. We enrolled 176 type 2 diabetic patients and 115 healthy subjects in a cross-sectional hospital-based study. Using fundus photographs documented retina statuses and using fluorescence polarization immunoassay measured homocysteine concentration. Risk factors for diabetic macular edema were obtained from fasting blood samples and interviewer- questionnaire. We found that diabetic patients had increased plasma homocysteine compared with normal control, and plasma homocysteine levels were higher in subjects with diabetic macular edema than without ((11.4 ± 2.7) vs. (8.5 ± 1.9) (μmol/l), p = 0.000). The association of homocysteine with diabetic macular edema was independent of major risk factors for diabetic macular edema (duration of diabetes, HbA1c, lipid) and determinants of higher homocysteine concentration (age, gender, serum folate and vitamin B12, renal status, and biguanide use) (OR: 1.63 (1.02-2.14), p = 0.018). Furthermore, a 1 μmol/l increase in plasma homocysteine concentration was associated with a 0.5% to 2.2% increase of diabetic macular edema and per increase of 5.0 μmol/l plasma homocysteine was significantly related to macular edema (OR: 1.64 (1.04-2.16), p = 0.019) after adjusting for duration of diabetes per 5 year increase, HbA1c per 1% increase, serum folate per 10 nmol/l increase, serum B12 per 100 pmol/l increase, serum creatinine per 10 μmol/l increase and urinary ACR per 5 mg/g increase. We concluded that hyperhomocysteinemia is independently associated with occurrence of macular edema in type 2 diabetes. Future prospective studies are warranted to clarify the relationship.