Epidemiology of proliferative diabetic retinopathy

This review examines recent epidemiological data about the prevalence and incidence of and risk factors for proliferative diabetic retinopathy. In addition, the relation of proliferative retinopathy to other systemic complications associated with diabetes is reviewed.

The data come mostly from the baseline and 4-yr follow-up examinations of a large population-based study, the WESDR, which involved 996 younger-onset insulin-dependent people whose diabetes was diagnosed at < 30 yr of age and 1370 older-onset people whose diabetes was diagnosed at > or = 30 yr of age, and who were taking or not taking insulin.

The major finding is that proliferative retinopathy is a prevalent complication (23% in the WESDR younger-onset group, 10% in the WESDR older-onset group that takes insulin, and 3% in the group that does not take insulin). Hyperglycemia, longer duration of diabetes, and more severe retinopathy at baseline were associated with an increased 4-yr risk of developing proliferative retinopathy. However, higher blood pressure at baseline was associated only with the development of proliferative retinopathy in the younger-onset group. The presence of proliferative diabetic retinopathy was associated with an increased 4-yr risk of loss of vision, cardiovascular disease, diabetic nephropathy, and mortality. In the WESDR, a significant number of diabetic people with proliferative retinopathy at risk for vision loss were not under the care of an ophthalmologist or had not undergone panretinal photocoagulation.

These data suggest that hyperglycemia and, possibly, high blood pressure are related to proliferative retinopathy. They also suggest that once proliferative diabetic retinopathy is detected, people should have a medical evaluation, because it is a strong indicator for the presence and development of systemic disease. These data also indicate that diabetic patients and their physicians should be aware of the need for routine ophthalmological examinations to detect and treat proliferative retinopathy.