Purpose: To evaluate the visual and anatomical outcomes of intravitreal ranibizumab for diabetic macular edema (DME) in the healthcare system of Taiwan.
Methods: A total of 39 eyes from 39 patients were retrospectively enrolled in the study. All eyes that fulfilled the key criteria, including a baseline vision between 20 and 70 ETDRS letters and a minimum central macular thickness (CMT) of 300 µm, had at least 3 monthly loading injections of ranibizumab in a year. Macular laser or posterior subtenon injections of triamcinolone acetonide (PSTA) could be performed as supplementary treatments following loading injections. Primary outcomes include best-corrected visual acuity and CMT.
Results: Patients' vision improved from 46.5 ± 15.3 letters at baseline to 51.4 ± 16.6 letters at 12 months (p = 0.031). Mean CMT at baseline was 406 ± 105 µm, which decreased to 329 ± 108 µm (p = 0.002). At 12 months, 44.4% of eyes with total injection number < 5 and 42.9% with injection number ≥ 5 achieved a gain in vision that was 10 letters or more. A total of 5 injections or more did not lead to a better visual gain in comparison with only 3-4 injections (p = 0.71), and both had similar number of supplementary treatments (p = 0.43). Monthly reinjections of ranibizumab resulted in a lower likelihood of visual loss of 10 or 15 letters (p = 0.019 and 0.015, respectively, adjusted for age, baseline vision, severity of diabetic retinopathy and the presence of previous treatments); however, supplementary macular lasers, PSTA or ranibizumab without monthly reinjections did not (all p > 0.05). The average number of injections was 4.3 ± 1.0.
Conclusion: Treatment for DME with at least three monthly ranibizumab loading injections, with or without other supplementary treatments, is effective at 12 months thereafter. Two monthly reinjections of ranibizumab, while not significantly increasing vision, may have a role in preventing visual loss.
Keywords: Best-corrected visual acuity; Diabetic macular edema; Intravitreal injections; Ranibizumab.