The Efficacy of Single-Dose Intravitreal Dexamethasone Implant for Diabetic Macular Edema Refractory to Anti-VEGF Therapy: Real-Life Results

INTRODUCTION: To investigate the efficacy, safety, and side effect profiles of a single-dose intravitreal dexamethasone implant (IDI, Ozurdex) in patients with diabetic macular edema (DME) refractory to anti-vascular endothelial growth factor (VEGF) therapy.
METHODS: This study included 101 eyes of 78 diabetic patients with DME that remained persistent despite administering at least six doses of anti-VEGF therapy. The patients were evaluated at baseline and were followed up monthly until the sixth month after the IDI injection. The primary outcomes were central foveal thickness (CFT) and best-corrected visual acuity (BCVA).
RESULTS: The mean number of anti-VEGF injection administered to patients was 6.50±0.33. One month after the last injection, the response to treatment was evaluated. IDI injection was performed approximately 1.14±0.08 months after the last anti-VEGF injection. After the IDI injection, BCVA value increased (p<0.001) and CFT value decreased (p<0.001). The peak effect of the IDI was observed in the second month after the injection. CFT values increased and BCVA values decreased from the beginning of the fourth month after the IDI injection. The recurrence rate of CFT elevation in the sixth-month follow-up was 57.4%. Moreover, we observed that high pre-injection CFT values were correlated with a high post-injection recurrence rate of CFT elevation (p<0.001).
DISCUSSION AND CONCLUSION: These findings suggest that the IDI injection significantly improves BCVA and CFT values in patients with DME refractory to anti-VEGF therapy. However, recurrence of CFT elevation may occur in >50% patients in the sixth month after the first injection.