Fasting homocysteine levels in adults with type 1 diabetes and retinopathy

Background and methods: Whether hyperhomocysteinemia is associated with diabetic retinopathy is still being debated. We measured homocysteine and thrombomodulin, a marker of endothelial cell damage, in patients with type I diabetes mellitus and retinopathy (n = 25) and in a well-matched group of diabetic patients without retinopathy (n = 23). All patients had normal serum creatinine and no macroalbuminuria. Results: Fasting homocysteine levels were higher in the group with retinopathy than in the group without retinopathy (8.75 +/- 1.9 vs. 7.69 +/- 1.6 mumol/l, P < 0.05). Microalbuminuria was more prevalent in the group with diabetic retinopathy and it correlated with homocysteine levels in this group (p < 0.05). Microalbuminuria was the most powerful independent determinant of homocysteine levels in multiple regression analysis in the group with retinopathy (p < 0.01). Thrombomodulin levels were not different in the two groups (36.6 +/- 9.7 vs. 34.9 +/- 11.1, p > 0.1) and there was no correlation between homocysteine and thrombomodulin levels in either group. Conclusions: The slight rise in homocysteine levels in patients with diabetic retinopathy was possibly caused by the early nephropathy as indicted by microalbuminuria. This small rise in homocysteine levels was not associated with endothelial dysfunction, as measured by serum thrombomodulin levels. (c) 2004 Elsevier B.V. All rights reserved.