Global rates of diabetic retinopathy and its vision-threatening endpoints soar

9 February 2012

MedWire News: Almost 93 million individuals were affected by diabetic retinopathy (DR) in 2010, with 28 million having vision-threatening diabetic retinopathy (VTDR), show findings published in Diabetes Care.

“This suggests that DR has the potential to be the leading cause of visual impairment and blindness worldwide,” say Tien Wong (University of Melbourne, Victoria, Australia) and team.

The researchers say their study provides the first global estimate of DR and, more importantly, the two sight-threatening endpoints: peripheral diabetic retinopathy (PDR) and diabetic macular edema (DME).

The findings arise from a pooled analysis of data from 22,896 individuals who participated in 35 population-based studies from the USA, Australia, Europe, and Asia. Wong et al determined the prevalence of DR and its sight-threatening endpoints as well as their relationship to key risk factors.

Most of the studies graded for DR using the Early Treatment Diabetic Retinopathy Scale or the American Academy of Ophthalmology International Clinical Diabetic Retinopathy Disease Severity Scale.

The researchers report that the age-standardized prevalence of any DR (defined as the presence of nonPDR, PDR, DME, or any combination) was 34.60%. The age-standardized prevalence of PDR was 6.96%, DME was 6.81%, and VTDR was 10.20%.

Extrapolating these prevalence rates to the 2010 world diabetes population, the team estimated that 92.6 million adults had any DR, 17.2 million had PDR, 20.6 million had DME, and 28.4 million had VTDR.

The researchers also report that the prevalence of any DR was significantly associated with diabetes duration (21.1 vs 76.3% for <10 vs ≥20 years), glycated hemoglobin level (18.0 vs 15.2% for ≤7.0 vs >9.0%), and blood pressure (30.8 vs 39.6% for ≤140/90 vs >140/90 mmHg), and was higher in people with Type 1 than Type 2 diabetes (77.3 vs 25.2%).

“We confirmed the importance and impact of three major modifiable risk factors – hyperglycemia, hypertension, and dyslipidemia – on the risk for all DR endpoints, including for the first time, PDR and DME,” says the team.

The authors also observed a trend towards a higher prevalence of VTDR stages, but not any DR, in people with total cholesterol levels of 4.0 mmol/L or more.

“This is particularly relevant to recent reports from trials suggesting that fenofibrate, a lipid-altering agent, may slow the development and progression of DR,” they write.

The authors say their results highlight the substantial public health effects of diabetes, and thus, the need for effective screening and management of DR risk factors.
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Diabetes Care 2012; Advance online publication