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. To describe 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 1876 people with type 1 diabetes (50% female, 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 presence of any moderate to severe non-proliferative or pre-proliferative diabetic retinopathy or proliferative diabetic retinopathy or maculopathy in either eye as per United Kingdom 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 1876 people, 359 (19%) developed STDR. People who developed STDR had higher baseline HbA1c, 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, hazard ratio (95% confidence intervals), African-Caribbean ethnicity (HR 1.39, CI 1.09-1.78, P=0.009), baseline SBP (HR 1.01 CI 1.00-1.01, p=0.033) and baseline HbA1c (HR 1.01 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.