Predictors for 2-Year Functional and Morphological Outcomes of a Treat-and-Extend Regimen with Ranibizumab in Patients with Diabetic Macular Edema

Purpose: The purpose of the study was to investigate longer term functional and morphological outcomes and their predictors in diabetic macular edema (DME) following a treat-and-extend regimen (TER) without loading dose under ranibizumab. Methods: Patient data were reviewed and analyzed retrospectively over a period of 24 months after initiation of TER. Best-corrected visual acuity (BCVA), treatment frequency, and quantitative and qualitative spectral-domain optical coherence tomography parameters were assessed. Results: 118 eyes of 87 patients were included. A mean of 9.74 +/- 2.13 injections in the first and 7.63 +/- 2.29 in the second year were applied. There were significant gains of BCVA and reductions in central retinal thickness from baseline to 12 and 24 months (all p < 0.001). Percentage of eyes with an intact inner segment/outer segment (IS/OS) junction increased from 15.3% at baseline to 42.1% at 24 months (p < 0.001). An intact IS/OS junction at baseline increased the probability of having a dry retina after 12 months by 79.3% (p = 0.017) and after 24 months by 88.1% (p = 0.040). Less IS/OS disruption at baseline predicted longer maximum recurrence-free treatment intervals at 2 years (r = -0.345, p < 0.001) and better BCVA at 1 year (r = -0.347, p < 0.001). Baseline bigger intraretinal cysts were associated with more IS/OS disruption at 24 months (r = 0.305, p = 0.007). Younger age and lower BCVA at baseline were predictive for a higher BCVA gain at 24 months (p = 0.046, p < 0.001). Conclusion: Ranibizumab applied in a TER without loading dose in DME significantly improves visual acuity and retinal anatomical structure throughout 2 years. The evaluated predictors might help guide routine clinical treatment in DME.