According to the study’s two-year findings, there was no visible improvement in vision even though preventative therapy decreased the risk of developing PDR or diabetic macular edema.
A clinical study by the DRCR Retina Network, funded by the National Eye Institute (NEI) of the National Institutes of Health, found that early treatment of diabetes-related eye disease slows progression to severe disease but does not improve visual acuity compared to treating severe disease once it occurs.
The findings of the study show “that monitoring patients regularly for vision-threatening diabetes complications and treating eyes only as needed is the best approach,” according to Raj Maturi, M.D., Indiana University School of Medicine and Retina Partners Midwest, who is the protocol chair for the four-year study.
The study’s findings were published in the Journal of the American Medical Association (JAMA) today.
Anti-vascular endothelial growth factor (anti-VEGF) drugs have been shown to significantly reduce the likelihood of vision loss due to diabetic retinopathy. However, there is uncertainty among eye care providers about the optimal timing for starting treatment. The administration of anti-VEGF involves an injection into the eye, which raises concerns about side effects, cost, and inconvenience. Therefore, physicians must carefully consider these factors before deciding to start treatment.
When diabetes damages the retina’s blood vessels, which detect light, diabetic retinopathy develops. Diabetes damages retinal blood vessels in its early stages, allowing fluid to flow into the surrounding retina. This stage of diabetic retinopathy is referred to as non-proliferative diabetic retinopathy (NPDR). Diabetic macular edema, a consequence of diabetic retinopathy, is a fluid accumulation in the retina that may result in visual loss. Vision may also be at danger if the condition worsens and develops into proliferative diabetic retinopathy (PDR), in which the retina develops new, abnormal blood vessels.
Researchers supported by the NEI looked at the possibility of preventing vision loss in NPDR patients by using the anti-VEGF drug Eylea (aflibercept). A total of 328 people participated in the research, and 399 eyes were analyzed (some volunteers had two eyes that met the criteria for enrollment in the study; others only had one study-eligible eye). 200 eyes received preventive anti-VEGF injections at one month, two months, four months, and subsequently every four months for two years. Treatment was given every four months for four years unless NPDR got better and became a mild disease. 199 eyes received sham injections over the same time frame, which included no medication. Any eye that had a problem that may have affected vision, such as macular edema or PDR, was given further anti-VEGF injections as needed.
The study’s results after two years showed that preventive treatment did lower the risk of getting diabetic macular edema or PDR, but it did not help people see better. The final, four-year findings confirm the prior finding, showing no statistically significant difference between the two groups in terms of visual acuity or rates of vision loss.
“We expected early treatment to prevent progression of diabetic retinopathy,” adds Adam Glassman, Jaeb Center for Health Research, Tampa, Florida, who directs the DRCR Retina Network coordinating center, “but even with preventative injections, about one-third of eyes developed vision-threatening complications.”
Disease development was seen in 34% of eyes getting preventative therapies during the course of the study’s four years, compared to 57% of eyes in the sham group. The average number of injections given to members of the preventative group was 11, compared to three for members of the sham group.
“While the individual risk of complications per injection is low,” remarks Jennifer Sun, M.D., M.P.H., Joslin Diabetes Center, Harvard Medical School, Boston, and chair of diabetes initiatives for the DRCR Retina Network, “the risk increases with each additional injection.
The results of this study show that the “anatomical benefit” of early “anti-VEGF treatment” does not lead to better vision.
“So it may not be worth the risk and inconvenience to the patient of repeat preventive injections for NPDR.”
Image Credit: Getty