Diabetes Drug May Slow Eye DiseasePosted: Updated:
Specifically, researchers found that patients who took the drug were less likely to develop proliferative diabetic retinopathy or to experience reductions in visual acuity (sharpness). But they are not recommending the drug's use until further studies are done.
In proliferative diabetic retinopathy, existing blood vessels in the retina are blocked or damaged, resulting in the formation of new, tiny blood vessels. The condition is one of the leading causes of severe vision loss among working-age Americans, and there are few effective therapies to slow its progression.
In this study, researchers compared 124 diabetes patients who took rosiglitazone and 158 diabetes patients who didn't take the drug or a similar medication. At the start of the study, 14 eyes of the people in the rosiglitazone group (9.3 percent) and 24 eyes of people in the control group (9.3 percent) had severe non-proliferative diabetic retinopathy, an earlier stage of proliferative diabetic retinopathy.
Of the patients with severe non-proliferative diabetic retinopathy, 7.7 percent of those in the rosiglitazone group and 29.2 percent of those in the control group progressed to proliferative diabetic retinopathy within one year. After three years, 19.2 percent of the rosiglitazone group and 47.4 percent of the control group had progressed to proliferative diabetic retinopathy. That works out to a 59.5 percent reduced risk for those taking the drug.
The study also found that 0.5 percent of the rosiglitazone group and 14.5 percent of the control group experienced a loss of visual acuity of at least three lines on the vision chart during an average of 2.8 years of follow-up.
The study is published in the June issue of the journal Archives of Ophthalmology.
Rosiglitazone may delay progression of retinopathy by reducing formation of new blood vessels, the researchers said.
"However, because this study does not rigorously prove that rosiglitazone either reduces the incidence of proliferative diabetic retinopathy or prevents loss of visual acuity, and because there may be adverse effects from therapy, rosiglitazone treatment of patients with diabetes specifically to reduce these ophthalmic complications is not advocated at this time," they wrote.
Rosiglitazone can cause such adverse effects as fluid build-up, abnormal liver function test, and worsening of congestive heart failure.
"Determination of the full efficacy and clinical role of rosiglitazone in the treatment of proliferative diabetic retinopathy and other angiogenic conditions awaits confirmation of risks and benefits and possibly large-scale definitive studies," the researchers concluded.
The National Eye Institute has more about diabetic retinopathy.
-- Robert Preidt
SOURCE: JAMA/Archives journals, news release, June 9, 2008
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