Visual Outcomes Following Intravitreal Ranibizumab for Diabetic Macular Edema in a Pro Re Nata Protocol from Baseline: A Real-World Experience

Purpose: To investigate long-term outcomes of pro re nata (PRN) treatment protocol of ranibizumab for diabetic macular edema (DME) adopted from the first month of therapy without 3 loading doses. Design: Retrospective interventional study. Methods: We analyzed 180 eyes of 144 patients treated with ranibizumab for DME with a minimum follow-up of 1 year during December 2013 to December 2017. Data of all patients with treatment-naive center-involving DME who received at least 1 intravitreal injection of ranibizumab during the study period were drawn from a locally adapted electronic form for DME. The primary outcome measure was change in best-corrected visual acuity (BCVA) from baseline at 1-year follow-up, with intergroup comparisons in BCVA between eyes receiving 1, 2, and 3 injections in the first 3 months of treatment. Results: The mean baseline BCVA was 0.47 +/- 0.30 logMAR, which improved to 0.38 +/- 0.3 logMAR (P = 0.003) at 3 months and stabilized at 0.35 +/- 0.27 logMAR at 1 year (P = 0.46 vs BCVA at 3 months) and 0.34 +/- 0.26 logMAR at 2 years of follow-up (P = 0.44 vs BCVA at 3 months). At 3 months, 24 eyes (13%) underwent 1 intravitreal injection, 52 eyes (29%) had 2 injections, and the majority (n = 104 eyes, 58%) had 3 injections on a monthly basis. During the first year, the group that received only 1 injection in the first 3 months also required fewer injections and fewer follow-up visits compared with those receiving 2 or 3 injections in the first 3 months. Conclusions: One-third of eyes with DME responded well to PRN treatment strategy from the first month without 3 loading doses of ranibizumab. Baseline visual acuity is the best predictor of vision at 1 and 2 years of follow-up.