Diabetic Retinopathy Study Suggests Reduced Prevalence in the United States

After decades of clinical advancements and public health efforts, ophthalmologists are witnessing fewer patients with diabetes develop diabetic retinopathy (DR) in the US. The decreasing disease prevalence was shown across ethnicities, something prior research rarely considered, according to a publication in the British Journal of Ophthalmology. In the 8-year study period, approximately 1 in every 5 participants with diabetes developed incident DR, whereas 23% of participants with DR showed improvement in disease severity, the study says.

The report reviewed 498 participants with diabetes between the ages of 45 and 84 years at baseline from the Multi-Ethnic Study of Atherosclerosis (MESA) study, sampled from 6 communities across the country. Researchers gathered retinal imaging from these patients 2 times approximately 8 years apart. The presence or severity of DR was graded from these images according to the modified Airlie House classification system. 

The study shows that patients with elevated blood pressure and poorer glycemic control were associated with an increased risk of incident DR. However, ethnic backgrounds were not statistically significant (P =.116), according to investigators. Patients who identified as Hispanics were most likely to develop vision-threatening DR (5.3%), followed by Black and Chinese American participants (both 1.8%) and White Americans (0.9%). 

Disease progression was associated with 2 primary factors: higher glycosylated hemoglobin and higher low-density lipoprotein cholesterol. 

“Of the 14 population-based studies with incidence data on DR, only 8 were conducted after the year 2000,” the report shows. Additionally, only 1 prior study was conducted within the US, the Los Angeles Latino Eye Study (LALES), which focused exclusively on Americans of Hispanic ethnicity. The LALES results did show the 4-year incidence of DR was 34%, and that progression of DR was 39%. 

Although the MESA research did note a higher incidence among the Hispanic group than other ethnicities, the 8-year DR incidence was only 22.5% and progression only 14.9%. This suggests a significant reduction in both categories in the years between studies. Researchers attribute some of these findings to advances in imaging technologies and an emphasis on earlier disease detection.

Limitations of this study include its relatively small sample size and the low incidence rates, which limited researchers’ ability to analyze less common but more severe forms of DR. 

Reference

Cheung N, Chee ML, Klein R, et al. Incidence and progression of diabetic retinopathy in a multi-ethnic US cohort: the Multi-Ethnic Study of Atherosclerosis. Br J Ophthalmol. Published online March 19, 2021. doi:10.1136/bjophthalmol-2021-318992