The Diabetic Retinopathy Clinical Research Network did not find a benefit of intravitreal triamcinolone relative to laser photocoagulation in patients with diabetic macular edema (DME) after 3-years of follow-up.
Macular edema is a frequent manifestation of diabetic retinopathy and an important cause of vision loss in these individuals. A clinical trial involving 693 subjects evaluated intravitreal triamcinolone (1- and 4-mg doses) compared with focal/grid photocoagulation for the treatment of DME.
The study found that there was an initial beneficial effect of 4 mg of triamcinolone at 4 months compared with a 1-mg dose or with focal/grid photocoagulation. However, the benefit diminished thereafter, and at 2 years, mean visual acuity was better in the laser group than in either of the other 2 groups. Optical coherence tomography (OCT) results paralleled the visual acuity results. Both triamcinolone doses, especially the 4-mg dose, were associated with an increased incidence of elevated intraocular pressure and cataract surgery.
Between 2 years (time of the primary outcome) and 3 years, more eyes improved than worsened in all 3 treatment groups. Change in visual acuity letter score from baseline to 3 years was +5 in the laser group and 0 in each triamcinolone group. The cumulative probability of cataract surgery by 3 years was 31%, 46%, and 83% in the laser and 1-mg and 4-mg triamcinolone groups, respectively. Intraocular pressure increased by more than 10 mm Hg at any visit in 4%, 18%, and 33% of eyes, respectively.
The researchers conclude that there was no long-term benefit of intravitreal triamcinolone relative to laser photocoagulation. Rather, visual acuity outcomes slightly favored the laser group over either of the 2 triamcinolone groups. It appears that most eyes receiving this 4-mg triamcinolone preparation will require cataract surgery, though only a few will develop glaucoma.
WHAT IT MEANS TO YOU: There is a great deal of interest in finding a safe and effective medical therapy for diabetic retinopathy. The finding that steroids could improve vision in persons with DME was met with great excitement. The standard therapy for DME is laser photocoagulation. Laser therapy is effective, but as with any surgical intervention, there are also associated risks. This study found that over 3 years steroid therapy is less effective and is associated with a higher risk of cataract and glaucoma. Studies are ongoing investigating the use of Avastin and Lucentis in the treatment of DME.
Source:http://www.ncbi.nlm.nih.gov/pubmed/19273785