The impact of Vitreo-Macular interface abnormalities on the response to Anti-VEGF therapy for centre involving diabetic macular oedema

Abstract

Abstract Background The influence of Vitreomacular Interface Abnormalities (VMIA) such as Epiretinal Membrane (ERM) and/or vitreomacular traction (VMT) on the response of patients with Centre Involving Diabetic Macular Edema (CIDME) to standard of care Anti-VEGF medications is under-researched. The aims of this study were: To determine the incidence of VMIA at baseline and 12 months amongst treatment naive patients commencing anti-VEGF treatment To compare the response to Anti-VEGF medications at 3 monthly intervals for 12 months in a large cohort of patients with and without VMIA on their baseline OCT scan. Response was determined in terms of: number of injections, central macular thickness and visual acuity. Methods A retrospective case notes review of treatment naïve patients with newly diagnosed CIDME. Included patients had been commenced on intravitreal Anti-VEGF injections (ranibizumab or aflibercept) at a single centre. Inclusion criteria were: treatment naïve DME patients with a CMT of 400μ or more receiving anti-VEGF treatment with at least 12 months follow up and in whom macular OCT scans and visual acuity (VA) measurements were available within two weeks of baseline, 3, 6, 9 and 12 months. Exclusion criteria included: previous intravitreal therapy, previous vitrectomy, cataract surgery during the follow-up period, concurrent eye conditions affecting vision or CMT. Results 119 eyes met the inclusion criteria and underwent analysis. Groups were comparable in their baseline demographics. Baseline CMT measurements were comparable at baseline (417μ and 430μ in the No-VMIA and VMIA groups respectively) and improved to approximately 300μ in both groups. From 6 months CMT continued to improve in the no-VMIA while progressively deteriorating in the VMIA group. Change in CMT was statistically different at 12 months between the 2 groups (108μ and 79μ, p= 0.04). There was a mean of 7 injections after 12 months. Conclusion Our study has shown a 46% incidence of VMIA amongst patients newly diagnosed with centre involving DME undergoing treatment with anti-VEGF injections. We have also demonstrated a significant difference in CMT and VA response to anti-VEGF treatment in patients with and without VMIA. Initial response was similar between the 2 groups up until 6 months. From 6 to 12 months significant differences in treatment response emerged. Differences in clinical response between patients with and without VMIA may help guide further prospective controlled studies and optimise treatment strategies.