The effect of glycaemic control on the quantitative characteristics of retinopathy lesions in patients with type 2 diabetes mellitus: 10-year follow-up study

Diabetic retinopathy (DR) represents a common complication of type 2 diabetes mellitus. Appearance of DR lesions such as microaneurysms, haemorrhages, hard and soft exudates, IRMA and neovascularisation reflect the severity of DR. The aim of our study was to investigate the association of selected glycaemic parameters with particular DR abnormalities and their characteristics in patients with type 2 diabetes. Eighty-three middle-aged patients with newly diagnosed type 2 diabetes mellitus participated in this 10-year prospective study. The glycaemic parameters such as glycated haemoglobin A1c (HbA1c), fasting blood/plasma glucose as well as 1- and 2-hour post-load glucose values were recorded at baseline, 5-year and 10-year follow-up. The fundus photographs were taken at baseline and then at 5-year and 10-year follow-ups and used for quantitative evaluation. Statistically significant positive correlations were found between all investigated 5-year glucose values and the extent of DR lesions at 10-year follow-up (p < 0.003). The 1- and 2-hour post-load glucose values correlated with the DR lesions with the highest significance (p a parts per thousand currency signaEuro parts per thousand 0.001). There were also associations between glycaemia and DR lesions investigated in a cross-sectional manner at 10-year follow-up. Binary logistic regression revealed that all glycaemic parameters at 5-year examination predicted the development of DR at 10-year follow-up (p a parts per thousand currency signaEuro parts per thousand 0.001). The most powerful predictor of DR was the 2-hour post-load glucose value, since it explained almost 50% of DR cases. Five-year blood glucose values predict the amount of DR lesions at 10-year follow-up in patients with recently diagnosed type 2 diabetes. The 2-hour post-load glucose at 5-year measurement appears to be the most reliable parameter predicting 10-year DR lesions.