The diabetes medication rosiglitazone has been associated with a reduction in the likelihood of developing the eye disease called proliferative diabetic retinopathy. A study published in the June issue of Archives of Ophthalmology also found that diabetes patients using the drug were less likely to have reductions in visual acuity (or sharpness).
Proliferative diabetic retinopathy is characterized by the creation of new, tiny blood vessels that form when existing retinal blood vessels are blocked or harmed. Although the disease is a frequent cause of vision loss in middle-aged Americans, we lack effective drugs that can delay its development.
The findings come from a study conducted by Lucy Q. Shen, M.D. (Jules Stein Eye Institute, University of California-Los Angeles) and colleagues that focused on the relationship between eye health and the drug rosiglitazone. The researchers collected data from medical records of 124 patients from the Joslin Diabetes Center in Boston. The patients were treated with rosiglitazone and were receiving medical and eye care at the center between May 2002 and May 2003. The rosiglitazone sample was then compared to 158 diabetes patients who were not being treated with rosiglitazone or a similar medication.
The initial analysis of the data revealed that 14 eyes (6.4%) in the rosiglitazone group and 24 eyes (9.3%) in the comparison group had an early stage of the disease called non-proliferative diabetic retinopathy (the new blood vessels had not yet formed). After one year, several of these eyes had progressed to proliferative diabetic retinopathy – 7.7% of the rosiglitazone group and 29.2% of the comparison group. Shen and colleagues calculated a 59.5% relative reduction in risk of progressing from the non-proliferative to the proliferative form of the disease for patients being treated with rosiglitazone. Only 19.2% of the rosiglitazone group, compared to 47.4% of the comparison group had progressed after three years.
The researchers also noted that during an average of 2.8 years of follow-up, eyes in the rosiglitazone group were less likely than the eyes in the comparison group to experience a loss in visual acuity of three or more lines on the vision chart – 0.5% to 14.5%, respectively.
The results of this analysis suggest that by preventing angiogenesis (the creation of new blood vessels), the medication rosiglitazone can potentially thwart the development of retinopathy and preserve visual acuity. “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,” write the authors. They mention fluid build-up, abnormal liver function test, and the worsening of congestive heart failure as probable adverse side effects.
They conclude that, “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.”
Rosiglitazone and Delayed Onset of Proliferative Diabetic Retinopathy
Lucy Q. Shen, MD; Angie Child, MD; Griffin M. Weber, MD, PhD; Judah Folkman, MD; Lloyd Paul Aiello, MD, PhD
Archives of Ophthalmology (2008). 126[6]:793 – 799.
Written by: Peter M Crosta