Researchers from King’s College London recently published a retrospective study in Diabetes Care outlining the impact of ethnicity on the development of sight-threatening diabetic retinopathy (STDR) in type 1 diabetes patients.
Give me some background.
Historically-speaking, most studies evaluating the risk factors and predictors for the progression of diabetic retinopathy (DR) have been in Caucasian patients with type 1 diabetes. Thus, there is limited information on the potential impact of ethnicity on the progression of diabetic retinopathy (DR) to STDR.
Talk about the study.
In this longitudinal data study, clinical and demographic data were collected from 1,876 patients with a diagnosis of type 1 diabetes who had no baseline evidence of retinopathy in either eye. Participants attended annual surveillance diabetes eye screenings in South London between 2004 and 2018.
The primary endpoint of the study was defined as the presence of any moderate to severe non-proliferative or pre-proliferative DR or proliferative DR or maculopathy in either eye.
Tell me about the cohort.
Within the study cohort, 50% were women; 72.1% of total participants were Caucasian; 17.3% were African Caribbean; 2.9% were Asian; and 7.6% were other ethnicities. The median age and duration of diabetes were 29 and 6 years, respectively, and the median length of follow-up was 6 years.
Study limitations?
Due to the retrospective nature of the study, investigators had to base the diagnosis on the type of diabetes using patient medical records and not a formal laboratory diagnosis.
Additionally, there was a lack of data and information on the medications and the smoking status of study participants.
Results?
The study found that people of African Caribbean descent with type 1 diabetes are at a 39% greater risk of STDR, which was found to be independent of conventional risk factors for DR progression and socioeconomic status.
Of the 1,867 participants, 359 (19%) progressed to STDR at the endpoint, and 1,442 did not over the course of follow-up.
Expert thoughts?
Evelyn Mensah, Clinical Lead for Ophthalmology at London North West University Healthcare NHS Trust, noted that there is evidence suggesting “racial differences in central retinal thickness (CTR) measurements, wherein the CRT is thinner in Black people compared to White counterparts.”
She added that, “this means more fluid would be required in a thinner macula compared to a thicker macula to be eligible for NICE-approved intravitreal anti-VEGF treatments.”
Significance?
The study authors concluded that patients of African Caribbean ethnicity and diagnosed with type 1 diabetes are at a significantly greater risk for STDR compared to other ethnicities.
Consequently, further analysis is needed to ascertain the exact reasons for this disparity.