Delayed anti-vascular endothelial growth factor therapy in patients with type 2 diabetes mellitus and branch retinal vein occlusion-associated macular edema negatively affects visual outcomes.

OBJECTIVE

To investigate the effect of delayed treatment on six-month visual outcomes in patients with type 2 diabetes mellitus (T2DM) complicated by branch retinal vein occlusion-associated macular edema (BRVO-ME).

METHODS

This single-center retrospective cohort study included 148 patients diagnosed with BRVO-ME and receiving their first intravitreal ranibizumab injection between January 2024 and May 2025. Patients were stratified according to the interval from diagnosis to initial anti-vascular endothelial growth factor (VEGF) injection into early treatment (≤7 days, n = 67), intermediate treatment (8-14 days, n = 52), and delayed treatment (>14 days, n = 29) groups. Baseline demographic, systemic, and ophthalmic parameters were collected. Best-corrected visual acuity (BCVA) and central macular thickness (CMT) (μm) were recorded at 1, 3, and 6 months post-injection. Multivariable linear regression was used to identify independent factors affecting six-month BCVA improvement.

RESULTS

All groups exhibited BCVA improvement and CMT reduction at six months, with the early treatment group showing the greatest improvement. Multivariable regression identified delayed treatment as the only independent factor associated with six-month BCVA improvement (β = -0.008, 95% CI: -0.014 to -0.002, P = 0.010). ROC analysis showed an AUC of 0.823 (95% CI: 0.751-0.884, P < 0.001) for delayed treatment predicting insufficient six-month visual improvement, with a sensitivity of 89.4% and specificity of 61.4% using a 14-day cutoff.

CONCLUSIONS

Initiation of anti-VEGF therapy within seven days of diagnosis is associated with greater six-month visual improvement in patients with BRVO-ME and T2DM. Delayed treatment may contribute to suboptimal visual recovery.