Purpose: The purpose of this study was to report the 24-month findings of a randomized clinical trial comparing intravitreal bevacizumab (IVB) injection alone or in combination with intravitreal triamcinolone acetonide (IVT) versus macular laser photocoagulation (MPC) as a primary treatment for diabetic macular edema.
Methods: The eyes were randomly assigned to 1 of the 3 study arms: the IVB group, patients who received 1.25 mg IVB; the IVB/IVT group, patients who received 1.25 mg of IVB and 2 mg of IVT; and the MPC group, patients who underwent focal or modified grid laser. Of 150 eyes (50 in each group) in the primary trial, 123, 119, and 113 eyes completed follow-ups at 12, 18, and 24 months, respectively. A total of 39 (78%), 36 (72%), and 38 (76%) eyes in the IVB, IVB/IVT, and MPC groups remained in the study within 24 months, respectively. Retreatment was performed at 3-month intervals whenever indicated. Data from a 24-month follow-up are presented. Changes in best-corrected visual acuity and central macular thickness up to 24 months were the main outcome measures in this study.
Results: Retreatment was required in 37 (94.9%), 27 (75.0%), and 31 (81.6%) eyes, respectively, in the IVB, IVB/IVT, and MPC groups up to 24 months. The significant superiority of visual acuity improvement in the IVB group, which had been noted at Month 6, did not sustain thereafter up to 24 months, and the difference among the groups was not significant at all visits. However, the mean visual acuity improvement was greater in the IVB group than the other groups and in the IVB/IVT group compared with the MPC group. The reduction of central macular thickness was more in the IVB group in relation to the other two treatment groups; however, the difference among the groups was not statistically significant at any of the follow-up visits.
Conclusion: In terms of vision improvement, the significant superiority of the IVB over the combined IVB/IVT and MPC treatment that had been observed at Month 6 did not sustain up to 24 months. This means that although IVB treatment may be a better choice than two other options in short term, the magnitude of this beneficial effect diminishes over time.
Trial registration: ClinicalTrials.gov NCT00370669.