Efficacy of dexamethasone intravitreal implant combined with anti-VEGF drugs in the treatment of diabetic macular edema: a systematic review and meta-analysis

Background Diabetic macular edema (DME) remains a leading cause of vision loss in diabetic patients. Although anti-vascular endothelial growth factor (anti-VEGF) agents are first-line treatments, corticosteroids like dexamethasone (DEX) intravitreal implant have shown potential synergistic effects. This meta-analysis aimed to evaluate the efficacy and safety of DEX intravitreal implant combined with anti-VEGF agents compared to anti-VEGF monotherapy. Methods A systematic search of PubMed, Embase, Web of Science, Science Direct, Wiley online, and Google scholar was performed up to April 2025. Primary outcomes were changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT). Meta-analyses were performed using Review Manager (RevMan) version 4.4.1. Results Eight studies comprising a total of 597 eyes were included in this meta-analysis. The pooled analysis demonstrated no statistically significant difference in BCVA between combination therapy and anti-VEGF monotherapy (Mean Difference [MD] = 1.79; 95% Confidence Interval [CI]: -1.68 to 5.26, P = 0.311). However, combination therapy resulted in a significantly greater reduction in CMT compared to anti-VEGF treatment alone (MD = -64.11 μm, 95% CI: -99.69 to -28.53, P < 0.001). The overall risk of bias across studies was rated as low to moderate. However, the incidence of adverse events is significantly higher in the combination therapy group. Conclusions DEX combined with anti-VEGF agents confers superior anatomical outcomes in reducing CMT compared to anti-VEGF monotherapy in the management of DME. However, further large-scale, multicenter randomized controlled trials with extended follow-up are warranted to validate these findings and optimize treatment protocols.