Background Diabetic macular edema (DME) is a leading cause of vision loss among working-age adults and represents a major burden on retinal services within the United Kingdom’s National Health Service (NHS). While randomized controlled trials have established the efficacy of intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents, real-world outcomes may differ due to variations in patient characteristics, treatment intensity, and service delivery. This study aimed to evaluate the effectiveness of anti-VEGF therapy for DME in routine NHS clinical practice. Methods A retrospective, multicenter, real-world cohort analysis was conducted using electronic medical record data from NHS hospital eye services. Adult patients with center-involving DME who initiated intravitreal anti-VEGF therapy (aflibercept, ranibizumab, or bevacizumab) between January 2018 and December 2023 were included. The primary outcome was change in best-corrected visual acuity (BCVA) at 12 months, measured in ETDRS letters. Secondary outcomes included changes in central retinal thickness (CRT), injection frequency, and treatment persistence. Results A total of 642 eyes from 642 patients were analyzed (mean age 64.8 ± 9.7 years; 58.1% male). Mean BCVA improved from 61.2 ± 13.9 ETDRS letters at baseline to 67.9 ± 14.1 letters at 12 months, representing a mean gain of +6.7 letters (p < 0.001). Visual gains of ≥10 and ≥15 letters were achieved in 34.6% and 18.9% of eyes, respectively. Mean CRT decreased by 117 μm over 12 months (p < 0.001). Eyes treated with aflibercept demonstrated greater visual and anatomical improvement compared with ranibizumab and bevacizumab. The mean number of injections during the first year was 7.1 ± 2.4. Lower baseline visual acuity and higher injection frequency were independent predictors of greater visual improvement. Conclusions In routine NHS practice, intravitreal anti-VEGF therapy provides meaningful visual and anatomical benefits for patients with DME, although outcomes are more modest than those reported in clinical trials. Treatment intensity and baseline visual acuity remain key determinants of response. These real-world findings support the effectiveness of anti-VEGF therapy in DME and highlight the importance of optimizing service delivery and adherence to maximize patient outcomes.

Diabetic macular edema; Anti-VEGF; Real-world evidence; NHS; Visual acuity; Optical coherence tomograph