Purpose: To evaluate the effect of three intravitreal injections of bevacizumab (IVB) alone or combined with triamcinolone (IVT) in the first injection for treatment of refractory diabetic macular edema (DME).
Methods: In this prospective, placebo-controlled, randomized clinical trial, 115 eyes of 101 patients with refractory DME were included. Subjects were randomly assigned to one of the three study arms: 1) three injections of IVB (1.25 mg/0.05 ml) at 6-week intervals, 2) combined IVB and IVT (1.25 mg/0.05 ml and 2 mg/0.05 ml respectively) followed by two injections of IVB at 6-week intervals, and 3) sham injection (control group). The primary outcome measure was change in central macular thickness (CMT). Secondary outcome measures were change in best-corrected logMAR visual acuity (BCVA ) and incidence of potential adverse events.
Results: Central macular thickness was reduced significantly in both the IVB and IVB/IVT groups. At week 24, CMT change compared to the baseline was -95.7 microm (95% CI, -172.2 to -19.26) in the IVB group, -92.1 microm (95% CI, -154.4 to -29.7) in the IVB/IVT group, and 34.9 microm (95% CI, 7.9 to 61.9) in the control group. There was a significant difference between the IVB and control groups (P = 0.012) and between the IVB/IVT and control groups (P = 0.022). Improvement of BCVA was initiated at weeks 6 and 12 in the IVB/IVT and IVB groups respectively. In terms of BCVA change compared to the baseline at 24 weeks, the differences between the IVB and control groups (P = 0.01) and also between the IVB/IVT and control groups (P = 0.006) were significant. No significant differences were detected in the changes of CMT and BCVA between the IVB and IVB/IVT groups (P = 0.99). Anterior chamber reaction was noticed in eight (19.5%) and seven (18.9%) eyes respectively in the IVB and IVB/IVT groups the day after injection, and it resolved with no sequel. Elevation of IOP occurred in three eyes (8.1%) in the IVB/IVT group.
Conclusion: Three consecutive intravitreal injections of bevacizumab had a beneficial effect on refractory DME in terms of CMT reduction and BCVA improvement. Addition of triamcinolone in the first injection seemed to induce earlier visual improvement; however, it did not show any significant additive effect later during follow-up.
Trial registration: ClinicalTrials.gov NCT00370422.