People With Type 1 Diabetes of African Caribbean Ethnicity Are at Increased Risk of Developing Sight-Threatening Diabetic Retinopathy

OBJECTIVE: There is limited information on the effect of ethnicity on the development of referable sight-threatening diabetic retinopathy (STDR) in people with type 1 diabetes. This study describes the risk factors for STDR in a diverse cohort of people with type 1 diabetes attending a regional diabetes eye screening service. RESEARCH DESIGN AND METHODS: Clinical and digital retinal imaging data from 1,876 people with type 1 diabetes (50% women, 72.1% Caucasian, 17.3% African Caribbean, 2.9% Asian, and 7.6% other) with no retinopathy at baseline, attending surveillance eye screening were reviewed. Referable STDR was defined as the presence of any moderate to severe nonproliferative or preproliferative diabetic retinopathy or proliferative diabetic retinopathy or maculopathy in either eye as per U.K. National Diabetic Eye Screening criteria. Median follow-up was 6 years. RESULTS: The median (interquartile range) age of the cohort was 29 (21, 41) years. Of the cohort of 1,876 people, 359 (19%) developed STDR. People who developed STDR had higher baseline HbA(1c), raised systolic blood pressure (SBP), longer diabetes duration, and were more often of African Caribbean origin (24% vs. 15.6%; P < 0.05 for all). In multivariable Cox regression analyses, African Caribbean ethnicity (hazard ratio [HR] 1.39, 95% CI 1.09–1.78, P = 0.009), baseline SBP (HR 1.01, 95% CI 1.00–1.01, P = 0.033), and baseline HbA(1c) (HR 1.01, 95% CI 1.00–1.01, P = 0.0001) emerged as independent risk factors for STDR. CONCLUSIONS: We observed that people with type 1 diabetes of African Caribbean ethnicity are at significantly greater risk of STDR. Further research is required to understand the mechanisms that explain this novel observation.