Glycated hemoglobin as a prognostic factor for the progression of non-proliferative diabetic retinopathy in type 2 diabetes

Background. A promising direction of modern medicine is to increase the accuracy of predicting the possible outcomes of the disease, its complications or relapses. Several factors are important for the progression of diabetic retinopathy (DR) in type 2 diabetes (T2D), among which glycated hemoglobin, duration of T2D and others are discussed. The purpose was to determine the possibilities of predicting the progression of initial non-proliferative diabetic retinopathy (NPDR) based on the blood glucose, glycated hemoglobin and cholesterol indicators. Materials and methods. Three hundred and fifty-eight patients (358 eyes) with T2D and DR were examined and divided into groups: the first one — with NPDR (189 eyes), the second one — with pre-proliferative DR (96 eyes) and the third one — with proliferative DR (73 eyes). Patients were examined for 2 years using ophthalmological methods; serum fasting glucose, glycated hemoglobin and total cholesterol were determined by colorimetric method. The analysis of the research results was carried out in the EZR v. 1.54 package (Austria). Results. There was no significant difference between the groups at baseline in terms of age and T2D duration; these indicators were not associated with the DR progression (p = 0.512 and p = 0.339, respectively) as well. The independent risk factors for the NPDR progression in the univariate analysis were the content of blood glucose (p = 0.002; odds ratio (OR) = 1.08; 95% confidence interval (CI) 1.03–1.13) and total cholesterol (p < 0.001; OR = 2.02; 95% CI 1.53–2.6 %). Based on the glycated hemoglobin blood level, a logistic model of the NPDR progression was constructed. The area under the receiver operating characteristic curve was 0.84 (95% CI 0.80–0.88), which indicated a strong association with the NPDR progression. The threshold for predicting the glycated hemoglobin level was 8.9 % with a sensitivity of 75.6 % (95% CI 68.6–82 %) and a specificity of 79.9 % (95% CI 73.5–85.4 %). Conclusions. It was found that the content of glycated hemoglobin in the blood above 8.9 % is an independent factor for the NPDR progression, which allowed to build a prognostic model with a very good quality of prognosis.