Ranibizumab for edema of the macula in diabetes study: 3-year outcomes and the need for prolonged frequent treatment

Objective: To assess the benefit of increased follow-up and treatment with ranibizumab between months 24 and 36 in the Ranibizumab for Edema of the Macula in Diabetes (READ-2) Study. Design: Prospective, interventional, multicenter follow-up of a randomized clinical trial. Methods: Patients who agreed to participate between months 24 and 36 (ranibizumab, 28 patients; laser, 22; and ranibizumab + laser, 24) returned monthly and received ranibizumab, 0.5 mg, if foveal thickness (FTH, center subfield thickness) was 250 μm or greater. Main outcome measures were improvement in best-corrected visual acuity (BCVA) and reduction in FTH between months 24 and 36. Results: Mean improvement from the baseline BCVA in the ranibizumab group was 10.3 letters at month 36 vs 7.2 letters at month 24 (ΔBCVA letters = 3.1, P = .009), and FTH at month 36 was 282 μm vs 352 μm at month 24 (ΔFTH=70 μm, P=.006). Changes in BCVA and FTH in the laser group (-1.6 letters and -36 μm, respectively) and the ranibizumab + laser group (+ 2.0 letters and -24 μm) were not statistically significant. The mean number of ranibizumab injections was significantly greater in the ranibizumab group compared with the laser group (5.4 vs 2.3 injections, P = .008) but not compared with the ranibizumab + laser group (3.3, P =.11). Conclusions: More aggressive treatment with ranibizumab during year 3 resulted in a reduction in mean FTH and improvement in BCVA in the ranibizumab group. More extensive focal/grid laser therapy in the other 2 groups may have reduced the need for more frequent ranibizumab injections to control edema. Application to Clinical Practice: Long-term visual outcomes for treatment of diabetic macular edema with ranibizumab are excellent, but many patients require frequent injections to optimally control edema and maximize vision.