Nine-year incidence of diabetic retinopathy in the Barbados Eye Studies

To estimate the 9-year incidence of diabetic retinopathy (DR) in a population with the same ancestry as African Americans.

Participants with diabetes mellitus and gradable photographs at the 9-year examination were evaluated (n = 436). The incidences of minimum/moderate/severe DR, clinically significant macular edema (CSME), and sight-threatening DR (severe DR plus CSME) were defined by the development of specific diabetic changes in persons without those conditions at baseline. Progression was defined as the development of severe/proliferative DR in persons with minimum/moderate DR at baseline.

The 9-year DR incidence was 39.6% (38.0% for minimum, 9.0% for moderate, and 2.6% for severe/proliferative DR). Incidence tended to increase with diabetes duration and treatment. Of persons with preexisting DR at baseline, 8.2% progressed to proliferative DR. The CSME incidence was 8.7%, and it increased with diabetes duration, accounting for most of the overall incidence of sight-threatening DR.

The study provides new data on long-term incidence among persons of African origin. Results suggest a possible lower risk of severe/proliferative DR than in whites, while CSME incidence seems comparable or higher. The main component of sight-threatening DR was CSME, highlighting the importance of DR as a cause of vision loss in this population.