Diabetic Retinopathy Risk Factors: Plasma Erythropoietin as a Risk Factor for Proliferative Diabetic Retinopathy

PURPOSE: The purpose of this study was to evaluate whether any stage of diabetic retinopathy (DR) is associated with levels of plasma erythropoietin and other plasma parameters. METHODS: It was examined a representative sample of 180 type 2 diabetes patients aged 40 to 79 years. Ophthalmic examination including a funduscopic examination, performed by an experienced ophthalmologist and the retinal finding were classified according to the grading system for diabetic retinopathy of ETDRS (Early Treatment Diabetic Retinopathy Study). It was measured the levels of plasma erythropoietin, cholesterol, triglyceride, apolipoproteins A and B, C-reactive protein, fasting blood glucose and hemoglobin A1C (HbA1C) in 88 DR patients and 92 controls without DR. Risk factors correlated with DR were compared between groups. RESULTS: The study group of 180 patients included 72 males and 108 females. The mean age of the patients with and without DR was 57.36 ± 8.87 years and 55.33 ± 8.28 years, respectively. Of the 88 patients with DR, only 9 (10%) had proliferative DR and the rest suffered from non-proliferative DR. The mean plasma levels of erythropoietin in proliferative DR group showed a significant difference in comparison to other groups. The mean plasma levels of cholesterol, triglyceride, apolipoproteins A and B, C-reactive protein, and fasting blood glucose were not significantly different in the three groups except for HbA1C. The absolute relative risk (ARR) also showed that erythropoietin was an increasing risk for proliferative DR (ARR, 1.17; 95% confidence interval, 1.060 to 1.420; odds ratio,1.060). CONCLUSIONS: Of the factors studied, erythropoietin level showed significant increase in proliferative DR group. The stepwise raised in mean plasma erythropoietin level which demonstrates significant correlation with proliferative DR versus remaining two groups, will be an indication of its role in proliferative DR.