Hyperhomocysteinemia in patients with diabetes mellitus with and without diabetic retinopathy

Objective. To evaluate the prevalence of hyperhomocysteinaemia in diabetic patients with no diabetic retinopathy (no DR), with non-proliferative diabetic retinopathy (NPDR) and with proliferative diabetic retinopathy (PDR). Research design and methods. This prospective, case-control study, included 179 diabetic patients and 156 age-matched controls with no diabetes and no history of ocular disease, who were undergoing routine physical checkups. Plasma homocysteine levels of all study participants were measured using high-performance liquid chromatography (HPLC). Hyperhomocysteinaemia was defined when homocysteine levels were higher than 15 μmol/l. Results. The mean plasma homocysteine level was 11.75±0.24 in the control group, 13.46±0.74 in the no DR group, 14.56±0.64 in the NPDR group and 15.86±1.34 in the PDR group. Mean homocysteine levels were significantly elevated in the NPDR and PDR groups compared to the control group (P=0.001 and <0.0001, respectively). The prevalence of hyperhomocysteinaemia was also higher in the NPDR and PDR groups compared to the control group (P=0.032 and 0.011, respectively). No statistically significant difference was found between the no DR and the control group. Conclusions. Our findings suggest that hyperhomocysteinaemia may be associated with diabetic retinopathy and partially explain the increased risk of microvascular angiopathy occurring in these patients.