Rosiglitazone may delay onset of proliferative diabetic retinopathy, study says

Rosiglitazone maleate, an oral peroxisome-proliferating activated receptor gamma-agonist, may delay the onset of proliferative diabetic retinopathy and reduce vision loss in patients with a severe nonproliferative form of the disease, a large, long-term study suggests. This may be attributable to the drug's antiangiogenic properties, the authors noted.

"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," they said.

Lucy Q. Shen, MD, and colleagues in Boston and Los Angeles reviewed the medical records of 124 patients with diabetic retinopathy who had been treated with Avandia (rosiglitazone maleate, GlaxoSmithKline) between May 1, 2002, and May 31, 2003. These records were then compared with a matched control group of 158 patients with diabetic retinopathy who had never been treated with a glitazone drug.

Follow-up averaged 2.8 years, ranging from 0.3 years to 9 years.

Baseline characteristics and final hemoglobin A1C values were 7.6% in the rosiglitazone group and 7.8% in the control group, the authors noted.

Among 14 eyes in the rosiglitazone group and 24 eyes in the control group that had severe nonproliferative diabetic retinopathy at baseline, 3-year rates for progression to proliferative diabetic retinopathy were 19.2% and 47.4%, respectively.

"When accounting for lost to follow-up and follow-up duration, this difference was statistically significant by the Wilcoxon method (P = .045) and neared significance by log-rank method (P = .059)," the authors said.

Fewer eyes in the rosiglitazone group experienced three or more lines of visual acuity loss (P = .03); however, the incidence of diabetic macular edema was similar in both groups, according to the study, published in the June issue of Archives of Ophthalmology.