Purpose: To report the efficacy of a single intravitreal bevacizumab injection alone or in combination with intravitreal triamcinolone acetonide versus macular laser photocoagulation (MPC) as primary treatment of diabetic macular edema (DME).
Methods: In this randomized, three-arm clinical trial, 103 eyes of 97 patients with clinically significant DME and no previous treatment were enrolled. The eyes were randomly assigned to one of three study arms: the intravitreal bevacizumab (IVB) group, patients who received 1.25 mg of intravitreal bevacizumab (37 eyes); the IVB/IVT group, patients who received 1.25 mg of intravitreal bevacizumab and 2 mg of intravitreal triamcinolone (33 eyes); and the MPC group, patients who underwent focal or modified grid laser (33 eyes). Primary outcome measure was change in visual acuity.
Results: Visual acuity changes +/- SD at 12 weeks were -0.22 +/- 0.23, -0.13 +/- 0.31, and + 0.08 +/- 0.31 logarithm of the minimal angle of resolution in the IVB, IVB/IVT, and MPC groups, respectively. The marginal regression model based on generalized estimating equation analysis demonstrated that the visual acuity changes in the groups were statistically significant at both 6 weeks (P < 0.0001) and 12 weeks (P = 0.024). The significant treatment effect was demonstrated at both 6 weeks and 12 weeks in the IVB group and only at 6 weeks in the IVB/IVT group. Significant central macular thickness (CMT) reduction was observed in eyes in the IVB and IVB/IVT groups only up to 6 weeks; however, CMT changes were not significant in the groups.
Conclusion: Up to 12 weeks, intravitreal bevacizumab treatment of patients with DME yielded better visual outcome than laser photocoagulation, although it was not associated with a significant decrease in CMT. No further beneficial effect of intravitreal triamcinolone could be demonstrated. Further clinical trials with longer follow-up are required to evaluate the long-term visual outcomes and complication profiles after primary treatment with such medications.