Association Between First- and Third-Month Responses to Intravitreal Ranibizumab for Diabetic Macular Edema

This work examines the relationship between first- and third-month anatomical and visual response with antivascular endothelial growth factor for diabetic macular edema.

We prospectively evaluated 58 eyes with center-involved diabetic macular edema. Response was categorized upon the anatomical status after 3 monthly doses based on the reduction of central macular thickness (CMT) from baseline (≥20% or not). Correlation analysis between the anatomical response status, gained letters, optical coherence tomography morphological features, and other baseline characteristics were obtained.

Twenty-five eyes (43.1%) achieved an anatomical reduction of ≥20% at the third month. Those with a reduction of ≥20% of CMT had subretinal fluid (P < .01), lower hemoglobin A_1c values (P < .01), lower proportion of intraretinal cysts (P < .01), a greater anatomical reduction, and visual improvement at the first month of treatment. Multiple logistic regression analysis, showed that the change of CMT after the first injection was an independent predictor for the anatomical reduction of ≥20% after the loading phase (P < .05). Best corrected visual acuity gain after the first dose showed a significant association with an improvement of ≥10 letters after the loading phase (P < .05), but not for macular thickness reduction.

First month anatomical reduction was associated with the anatomical response at 3 months (P = .042) after monthly ranibizumab therapy. Visual improvement at the first month was predictive only for the visual outcome after the 3 monthly doses (P = .032).