Real-world injection burden, treatment switching, and visual outcomes in diabetic macular edema: a 563-eye cohort study

To evaluate real-world injection burden, treatment switching patterns, and visual outcomes in patients with diabetic macular edema (DME) receiving intravitreal anti–vascular endothelial growth factor (anti-VEGF) therapy. This retrospective observational cohort study included 563 eyes with DME treated with anti-VEGF agents and followed for at least 12 months. All eyes received an initial loading phase of three monthly bevacizumab injections followed by a pro re nata regimen. Primary outcomes were the number of injections and outpatient visits during the first year. Secondary outcomes included change in best-corrected visual acuity (BCVA), distribution of visual outcomes, and treatment switching patterns. Multivariable linear regression and generalized estimating equation (GEE) analyses were performed to identify independent predictors of visual outcomes. Eyes received a mean of 5.4 ± 2.4 injections and attended 8.0 ± 2.2 visits during the first year. Mean BCVA improved from 0.75 ± 0.43 to 0.59 ± 0.42 logMAR (mean change − 0.16 ± 0.35; P < 0.001). Visual improvement was observed in 60.2% of eyes, stability in 21.7%, and deterioration in 18.1%. Treatment switching occurred in 29.7% of eyes, typically within the first 4–5 months. In multivariable linear regression analysis, baseline BCVA was associated with visual acuity change (β = −0.33, P < 0.001). Treatment switching was associated with visual outcomes in unadjusted analysis but was not independently associated after adjustment. In the GEE analysis accounting for inter-eye correlation, baseline BCVA remained significantly associated with visual acuity change ( P < 0.001), whereas injection number ( P = 0.527) and treatment switching ( P = 0.976) were not associated. In real-world clinical practice, anti-VEGF therapy for DME was associated with meaningful visual improvement despite a moderate injection frequency. Visual outcomes were primarily associated with baseline visual acuity rather than treatment intensity. Treatment switching was not independently associated with visual acuity change after adjustment, suggesting that it likely reflects underlying disease refractoriness rather than acting as an independent factor associated with visual outcomes; however, causal inference cannot be established due to the observational study design. These findings underscore the importance of individualized treatment strategies in DME.