Abstract Objective To evaluate the relationship among Diabetic retinopathy (DR), insulin resistance (IR) and blood homocysteine (Hcy) and to discuss the influence of amino acid metabolism on the pathogenesis and development of DR and the effect of IR on Hcy. Methods T2DM group (according to the WHO diagnosis criteria of type 2 diabetes in 1999) with 125 the aged in-patients of endocrinology department was divided into a group with type 2 diabetic retinopathy (DR group, 63 cases) and a group without retinopathy complications (NDR group, 62 cases). And the DR group was subdivided into background diabetic retinopathy group (BDR, 30 cases) and proliferative diabetic retinopathy (PDR, 33 cases). Fasting blood glucose (FBG), fasting insulin (FINS), the blood lipids include the total cholesterol (CHO),the triglyceride (TG) et al, were measured for T2DM group and 50 control subjects (CON group). Then those patients with diabetes were divides into high Hcy group (HHcy group) and normal Hcy group, according to the Hcy plasma level. And clinical indicators were compared between the two groups. Hcy was measured with enzyme linked immunosorbent assay by enzymatic reader. HOMA-IR was calculated. All of clinical data were analyzed retrospectively. Results 1 Plasma total Hcy level was significantly higher in the DR group [(15.78±3.52)umol/l] than in the NDR group [(13.45±2.29) umol/l] and the CON group [(11.91±2.30)umol/l ](p<0.01). And it increased with the severity of retinopathy. 2 Compared with the normal Hcy group, patients with the HHcy group had higher levels of FBG, HbA1C and HOMA-IR.(p<0.05) 3 By stepwise regression analysis, FBG, HbA1C and HOMA-IR were the decisive and independent factors of plasma Hcy level in type 2 diabetes. 4 Diabetic retinopathy(yes or not) as dependent variable and age, sex, body mass index(BMI)、CHO、TG、HbA1c and HOMA-IR as independent variable, Logistic regression analysis results showed that disease course, HbA1c, and Hcy were correlat |