Intravitreal Dexamethasone Implant in Anti-Vascular Endothelial Growth Factor Pretreated Diabetic Macular Edema-A Swiss Cohort Study.

Abstract

Diabetic macular edema (DME) is a significant cause of visual impairment, often treated with anti-vascular endothelial growth factor (anti-VEGF) agents. However, some patients do not respond adequately to this treatment. This study aims to evaluate the contribution of the intravitreal dexamethasone (DEX) implant as a second-line treatment in DME patients with insufficient response to anti-VEGF therapy or with high treatment burden. This retrospective multicenter cohort study was conducted across seven clinical sites in Switzerland. The study included eyes with active DME that had been pretreated with anti-VEGF for at least six months before receiving DEX therapy. Data were extracted from electronic patient records, focusing on best-corrected visual acuity (BCVA), central subfield thickness (CST), and injection frequency. A total of 95 eyes from 89 patients (38.8% females, mean age 65.6 ± 9.1 years, follow-up time 80.6 ± 38.5 [13.5-166.7] months) were analyzed. Prior to the first DEX implant, eyes had undergone an average of 16.0 ± 13.3 anti-VEGF injections over 32.5 ± 22.4 months. Post-DEX treatment, 22.1% of eyes received DEX monotherapy, 44.2% received a combination of DEX and anti-VEGF, 25.3% continued with anti-VEGF monotherapy, and 8.4% received no further treatment. The number of anti-VEGF injections decreased significantly from 6.4 ± 3.1 in the year before DEX to 1.6 ± 2.4 in the year after DEX (p < 0.001). BCVA remained stable (0.4 ± 0.3 logMAR at baseline, 0.4 ± 0.5 logMAR at 24 months, p = 0.2), while CST improved from 477.7 ± 141.0 to 320.4 ± 125.5 μm (p < 0.001), and the presence of retinal fluid decreased from 98.0% to 61.1% (p = 0.021). During follow-up, 26.3% of eyes required glaucoma medication, 4.2% underwent glaucoma surgery, and 1.1% needed cataract surgery. In real-world clinical settings, the addition of DEX to anti-VEGF therapy in DME patients significantly reduces treatment burden and retinal fluid while maintaining visual function. Treatment decisions should balance anatomical and functional outcomes, considering individual patient needs.