Findings about diabetic eye disease may lead to improved screenings and treatment for people with diabetes

Sep 10 2004

Eli Lilly and Company have announced key findings from analyses of prior study data that enhances understanding of vision loss due to diabetic retinopathy, a diabetic microvascular complication that affects an estimated 50 million people worldwide.

Data presented at the 40th Annual Meeting of the European Association for the Study of Diabetes (EASD) pinpoint a critical phase in the progression of diabetic macular edema, a manifestation of diabetic retinopathy, and suggest that earlier treatment may minimize vision loss in people with diabetes.

Diabetic retinopathy, along with diabetic neuropathy (nerve damage) and diabetic nephropathy (kidney damage), is one of the three diabetic microvascular complications. Diabetic retinopathy, including diabetic macular edema, results from damage to the small blood vessels in the eyes. Diabetic retinopathy is the leading cause of blindness worldwide in working-age adults and can lead to progressive vision loss long before blindness.

"As the number of diabetes cases continues to surge globally, so does the prevalence of diabetic eye disease, including diabetic macular edema. Despite improved diabetes therapies, approximately 10 percent of patients will develop severe vision loss within 15 years of diagnosis and 2 percent of patients will become blind," said Louis Vignati, M.D., medical director, Eli Lilly and Company.

Diabetic macular edema can occur at any stage of diabetic retinopathy. It is produced by leakage of fluid from damaged retinal blood vessels. The macula is an area near the center of the retina responsible for daytime visual acuity. Visual acuity is most impacted when swelling occurs at the center of the macula.

Data presented at EASD explored visual acuity in people with various stages of diabetic macular edema to better understand how the distance of the leakage from the macular center impacts vision loss. Findings suggested that patients have higher risk of vision loss when diabetic macular edema progresses to the center of the macula. These data suggest the key to minimizing vision loss is earlier detection through increased screenings and development of treatments that inhibit progression toward the center of the macula.

The analyses included 939 patients with various levels of diabetic macular edema who participated in two clinical trials (PKC-DRS and PKC-DMES) for Lilly's ruboxistaurin, a compound currently being investigated as a possible treatment for diabetic retinopathy and other diabetic microvascular complications. Ruboxistaurin is not approved for use in Germany, Europe or elsewhere in the world.

Patients in the PKC-DRS trial had various degrees of diabetic macular edema, ranging from none to center involvement at baseline. Twenty-six percent of them experienced sustained moderate vision loss. Visual impairment did not occur until the center of macula was involved.

Data from the PKC-DMES trial showed that 33 percent of patients with retinal thickening greater than 500 microns from the center of the macula eventually developed center thickening. Comparatively, 50 percent of patients with retinal thickening within 500 microns from the center went on to develop diabetic macular edema involving the center of the macula. These data suggest the closer diabetic macular edema gets to the center of the macula, the more likely it is to eventually involve the center and impair vision.

"These findings bring us one step closer to understanding where the window of opportunity is to minimize the impact of diabetic macular edema. It is critical that we continue to seek improved treatments and encourage screenings and early detection to help improve outcomes for the 150 million people living with diabetes," said Dr. Pawel Fludzinski, team leader for Lilly's ruboxistaurin effort.

The World Health Organization recommends regular eye examinations for people with diabetes, yet research indicates that in both developed and developing countries, eye examinations are underutilized due to lack of awareness and limited accessibility to testing.