Objective: To report 5-year outcomes from a clinical trial of intravitreal triamcinolone acetonide (IVTA) in eyes with diabetic macular edema (DME) and impaired vision despite previous laser treatment.
Design: Prospective, double-masked, randomized clinical trial. After completing the 2-year visit, all eyes, including those initially randomized to receive placebo, received IVTA according to prospectively defined guidelines.
Participants and controls: A total of 69 eyes (41 patients) were entered into the study, with 34 eyes initially receiving active treatment and 35 eyes receiving placebo. Five-year data were available for 44 of 67 eyes (66%). For the 23 eyes with missing 5-year data, of which 13 received placebo and 10 received IVTA, the last observation was carried forward.
Intervention: Intravitreal injection of 0.1 ml of 40 mg/ml triamcinolone acetonide with adjunctive laser therapy where appropriate.
Main outcome measures: Improvement of best-corrected logarithm of the minimum angle of resolution visual acuity by >or=5 letters after 5 years compared with baseline and 2 years, and incidence of adverse events. Secondary outcome was the change in central macular thickness.
Results: Improvement of >or=5 letters after 5 years was found in 14 of 33 eyes (42%) initially treated with IVTA compared with 11 of 34 eyes (32%) initially treated with placebo (z(GEE) = 0.81, P = 0.4). Foveal thickness decreased by 30 microm (95% confidence interval, -47 to 107 microm) less in the initial-IVTA group than in the initial-placebo group at 5 years (z(GEE) = 0.76, P = 0.45); 5 of 11 eyes (45%) from the initial-IVTA group that were phakic at commencement of the third year required cataract surgery. A similar number of eyes from each group required ongoing treatment from the third year onward with both laser and IVTA, indicating that IVTA treatment for 2 years does not lead to reduction in the risk of recurrent edema.
Conclusions: The majority of eyes that initially improved with IVTA maintained their gain after 5 years. No new safety concerns were identified. IVTA treatment may be considered in carefully selected cases of impaired vision caused by advanced DME that are unresponsive to other interventions.