Résultats anatomiques et fonctionnels du protocole thérapeutique « 3 + PRN » dans le traitement de l’œdème maculaire diabétique

Abstract

Purpose: To evaluate the anatomical and functional results of the “3 + PRN” protocol in the treatment of diabetic macular edema (DME), determine the predictive factors for good final visual acuity, and compare it to other protocols.Materials and methods: We conducted a retrospective, descriptive, comparative, cross-sectional study of patients with DME, which we dubbed HTSM. All patients were treated with three monthly initial intravitreal injections (IVT) of 1.25 mg bevacizumab and followed according to the pro re nata (PRN) protocol for a period of 3 years. The protocol was based on a monthly monitoring schedule for the first 3 months, then increasingly spaced out over time. “On-demand” treatment was indicated with resumption of bevacizumab IVT in the event of worsening of DME.Results: A total of 52 patients were included. The mean age was 65 years. Type 2 was the most frequently observed type of diabetes. The mean duration of the PRN protocol was 6 months, and the mean number of injections was 6. The mean visual acuity (VA), initially 1/10, improved to 3/10 by the conclusion of the 3+PRN protocol, with an improvement of more than 5 letters in 77.6% of cases. The mean initial central macular thickness (CMT) was 451.5 µm. The final mean EMC decreased to 298.5 µm, which corresponds to a reduction of 153 µm compared to the initial value. The mean subfoveal choroidal thickness, initially 304.2 µm, decreased to a mean of 284.5 µm at completion. Comparative analysis of the results before and after the PRN protocol confirmed the existence of a statistically significant correlation between VA and CMT (p<0.05). No correlation was observed between age and visual acuity or between initial and final VA. The analysis of the various tomographic parameters and VA revealed a significantly better visual improvement in the group in whom the external limiting membrane (MLE) and ellipsoid zone (ZE) were intact (p = 0.04), as well as in the group in whom serous retinal detachment (SRD) was absent (p<0.001). Posterior vitreous detachment (PVD) was the most frequently observed vitreomacular anomaly. The final VA was similar in the groups with and without PVD (p = 0.04).Conclusion: The 3+PRN protocol is effective both functionally and tomographically in the treatment of DME. Various tomographic parameters might influence therapeutic efficacy. However, further in-depth studies are needed to better investigate these parameters.