Good blood glucose control characterizes patients without retinopathy after long diabetes duration

The importance of blood glucose control for the avoidance of retinopathy was assessed by monitoring glycated haemoglobin for 5 years or more in Type 1 (insulin-dependent) diabetic patients diagnosed before an age of 31 years, and with a diabetes duration of 20 years or more. They were followed up for an average of 9.4 years with 3.3 measurements per year. Of the 213 included patients, 16 had no retinopathy, 126 had background retinopathy (including 8 with macula oedema) and 71 had proliferative retinopathy. patients without retinopathy had a mean HbA1c +/- SEM for the whole follow-up period of 6.3 +/- 0.19%, the 117 patients with background retinopathy but not macula oedema 7.0 +/- 0.08%; Mann-Whitney test vs group without retinopathy p = 0.003, macula oedema 7.9 +/- 0.31%; p = 0.001, and proliferative retinopathy 7.4 +/- 0.09; p < 0.001. The mean duration was 31 years, without significant differences between the groups. In conclusion, these results suggests that good blood glucose control is of major importance to prevent or postpone diabetic retinopathy also after long duration of diabetes, and that no patient with high HbA1c levels for several years is protected from retinopathic lesions.