Epidemiology of Diabetic Retinopathy
Diabetes mellitus is a growing global epidemic that is expected to affect 642 million individuals by the year 2040, leading to an associated increased prevalence of diabetic retinopathy worldwide. One-third of the global population of individuals with diabetes mellitus is estimated to have diabetic retinopathy; of that group, one-third is likely to have vision-threatening diabetic retinopathy.
An important epidemiologic finding of the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) was the direct association of an increased prevalence of diabetic retinopathy with longer duration of diabetes mellitus in patients with both type 1 and type 2 diabetes mellitus. In the WESDR cohort, after 20 years of diabetes mellitus, nearly 99% of patients with type 1 and 60% with type 2 disease demonstrated some degree of diabetic retinopathy. Proliferative diabetic retinopathy was found in 50% of type 1 patients who had 20 years’ duration of disease and in 25% of type 2 patients who had 25 years’ duration of disease. Furthermore, 3.6% of younger-onset patients (aged <30 years at diagnosis) and 1.6% of older-onset patients (aged 30 years or older at diagnosis) were found to have a visual acuity of 20/200 or worse. Such vision loss was attributable to diabetic retinopathy in 86% of the younger-onset patients and in 33% of the older-onset group.
WESDR epidemiologic data were based largely on white populations of northern European descent and therefore are not entirely applicable to other racial groups. According to the United States Centers for Disease Control and Prevention, in 2011, the age-adjusted percentage of adults with diagnosed diabetes mellitus who reported visual impairment was 20.7% for black participants, 17.1% for white participants, and 15.6% for Hispanic participants. Recent studies have suggested that rates of diabetic retinopathy progression and vision loss are lower in the modern era due to improvements in systemic control and treatment advances.
Centers for Disease Control and Prevention. Diabetes Report Card 2017. Atlanta, GA: Centers for Disease Control and Prevention, US Dept of Health and Human Services; 2018. Available at https://www.cdc.gov/diabetes/pdfs/library/diabetesreportcard2017-508.pdf. Accessed December 18, 2019.
International Diabetes Federation website. Diabetes: Facts and figures. Available at https://www.idf.org/about-diabetes/what-is-diabetes. Accessed March 15, 2018.
Klein R, Lee KE, Knudtson MD, Gangnon RE, Klein BE. Changes in visual impairment prevalence by period of diagnosis of diabetes: the Wisconsin Epidemiologic Study of Diabetic Retinopathy. Ophthalmology. 2009;116(10):1937–1942.
Yau JW, Rogers SL, Kawasaki R, et al; Meta-Analysis for Eye Disease (META-EYE) Study Group. Global prevalence and major risk factors of diabetic retinopathy. Diabetes Care. 2012;35(3):556–564.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.