Microaneurysms in the development of diabetic retinopathy (UKPDS 42)

Aims/hypothesis. To determine whether microaneurysms, in the absence of oth er lesions, have a predictive role in the progression of diabetic retinopat hy in Type II (non-insulin-dependent) diabetes mellitus. Methods. Retinal photographs taken at diagnosis in patients participating i n the United Kingdom Prospective Diabetes Study, and thereafter at 3 yearly intervals, were assessed using a modified Early Treatment of Diabetic Reti nopathy grading system for lesions of diabetic retinopathy and end points o f vitreous haemorrhage and photocoagulation. The number of microaneurysms i n each eye was recorded. Results. The changes between diagnosis and later photographs were analysed in 2424 patients at 6 years, 1236 at 9 years and 414 at 12 years. Of the 24 24 patients studied in the 6 year cohort 1809 had either no retinopathy or microaneurysms only at entry. In these patients the presence of microaneury sms alone and also the number of microaneurysms had a high predictive value for worsening retinopathy at 3, 6, 9, and 12 years after entry into the st udy (e. g, at 6 years; chi(2) for trend = 75 on 1 df, p < 0.001). The predi ctive value of the presence or absence of microaneurysms and their number a t 3 years from diagnosis and subsequent worsening retinopathy was similar t o that at entry. Conclusion/interpretation. Microaneurysms are important lesions of diabetic retinopathy and even one or two microaneurysms in an eye should not be reg arded as unimportant.