Differential response to intravitreal dexamethasone implant in naïve and previously treated diabetic macular edema eyes

BACKGROUND: To identify different response patterns to intravitreal dexamethasone implants (IDI) in naïve and previously treated (PT) diabetic macular edema (DME) eyes in a real-life setting. METHODS: 342 IDI injections (203 DME eyes) were included. Number of IDI injections, percentage (%) of eyes with 1, 2, 3 and ≥ 4 injections, time to reinjections, visual acuity (VA), intraocular pressure (IOP) and central retinal thickness (CRT) were evaluated for naïve and PT DME eyes over 24 months. RESULTS: Mean number of injections was significantly lower in naïve vs PT DME eyes (1.40 ± 0.9 vs 1.82 ± 0.9, p < 0.001). The percentage of eyes receiving 1 injection was significantly higher in naïve vs PT DME eyes (76.1 vs 47.7), (p < 0.001). However, it was significantly lower for 2 (16.4 vs 29.4), or 3 injections (1.4 vs 17.6) (both p < 0.001), with no differences in eyes receiving ≥4 injections (5.9 vs 5.1 respectively, p = 0.80). Mean time to reinjection was not significantly different between both groups for the second, third and fourth injection (9.6 ± 4.0 vs 10.0 ± 5.5, p = 0.75, 13.2 ± 4.0 vs 16.0 ± 3.5, p = 0.21 and 21.7 ± 3.8 vs 19.7 ± 5.8, p = 0.55). VA scores were consistently better in naïve vs PT DME eyes at all studied timepoints, with no significant differences in CRT reduction or adverse effect rates. CONCLUSION: Naïve DME eyes received lower number of IDI injections and showed better VA levels than PT DME eyes for 24 months in a real-world setting. This data supports the IDI use in early DME stages and provide further evidence of better IDI response when used as first-line therapy.