Abstract
Purpose: :
Detection and management of diabetic retinopathy (DR) has changed considerably since the publications of the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) 25 years ago. However, it is unclear whether there has been a change in the prevalence of DR over time. We examined the DR prevalence from epidemiological studies around the world to identify possible time trends, which may have implications for the design of future clinical trials.
Methods: :
We conducted a systemic review of all published data on the prevalence of non-proliferative DR (NPDR), proliferative DR (PDR), and diabetic macular edema (DME) for the period 1980-2006 (with half of the studies completing recruitment before 2001). We compared studies between persons with type 1 and type 2 diabetes and between populations from different countries and/or different ethnicities.
Results: :
27 studies were identified, yielding 33,411 participants (with 2,124 type 1 and 31,287 type 2 diabetes). In studies of type 1 diabetes, the prevalence of DR was clustered around 45% (35-54%). The prevalence of PDR was around 4.5% and for DME, around 10%. In contrast, in studies of persons with type 2 diabetes, a wide range of DR prevalence was observed, ranging from 10% to 50%. The prevalence of vision threatening complications (PDR and DME) was also highly variable, especially among populations of different ethnic backgrounds.
Conclusions: :
A high prevalence of DR and PDR in contemporary epidemiological studies was observed. Prevalence rates were uniform in studies of type 1 diabetes, but variable in studies of type 2 diabetes. This difference may reflect the relative contributions of genetic versus environmental and behavioral factors in the development of diabetic microvascular complications, as well as differences in the detection and management of DR in type 1 versus type 2 diabetics.
Keywords: diabetic retinopathy • retina • retinal neovascularization