Progression to proliferative retinopathy and macular oedema requiring treatment. Assessment of the alternative classification of the Wisconsin Study

Purpose: To study the ability of the alternative classification of the Wisc onsin Study to predict progression to retinopathy requiring laser treatment in patients with diabetes. Methods: A total of 1585 diabetic patients were included in the study Of th em, 294 (19%) were diagnosed with diabetes before and 1291 (81%) after age 30 years. Retinopathy was diagnosed on fundus photographs using a modificat ion of the Wisconsin scale, and graded into 6 levels according to the,worse eye. The first visit during the study period was used to represent baselin e examination. The time paints for detection of proliferative retinopathy ( PDR) and clinically significant macular oedema (CSME) were recorded during a mean follow-up time of 2.9 years. Results: Progression to PDR and/or CSR;IE was significantly related to incr easing severity of retinopathy at baseline (p<0.001; test for trend). Fifty per cent of patients with severe non-proliferative retinopathy (NPDR) (lev el 51) at entry progressed within one year to PDR and/or CSME; the 3-year r isk for such progression in patients with mild (level 31) and moderate NPDR (level 41) was 25 and 60%, respectively, The incidence of progression to P DR and to CSME was 0.95 and 2.3/100 person-years, respectively, Progression to PDR and/or CSME was furthermore associated with a higher level of glyco sylated haemoglobin, longer duration of the diabetes and use of antihyperte nsive treatment. Conclusion: Increasing severity of retinopathy as recorded by this modifica tion of the alternative classification of the Wisconsin Study was significa ntly associated with increased risk of progression to retinopathy requiring treatment.