The Pattern of Recurrence in Diabetic Macular Edema Treated by Dexamethasone Implant: The PREDIAMEX Study

Purpose To assess the time to functional and anatomic recurrence of macular edema (ME) after a first intravitreal dexamethasone implant in eyes with diabetic macular edema (DME). Design A 6-month observational, prospective, uncontrolled, multicenter, national case series. Participants Thirty-seven patients included between January 2015 and June 2016. Methods Patients were monitored at baseline and then monthly over 6 months after the first treatment. Main Outcome Measures Different patterns of recurrence were defined: qualitative and quantitative anatomic recurrences and functional recurrence. Results Median ME duration before the first dexamethasone implant was 2.04 months. All patients received a dexamethasone implant for the first time, but 73% of patients had not undergone any form of treatment previously. The mean time from baseline to qualitative anatomic, quantitative anatomic, and functional recurrence was 4.22 months (95% confidence interval [CI], 3.80–4.65 months), 4.73 months (95% CI, 4.34–5.12 months), and 4.89 months (95% CI, 4.53–5.26 months), respectively. Almost all patients (7/8) who demonstrated a qualitative anatomic recurrence showed a subsequent quantitative anatomic and functional recurrence days later. Mean improvement in best-corrected visual acuity was 10.1 letters (95% CI, 6.7–13.4 letters) and 7.3 letters (95% CI, 4.1–10.6 letters) at months 2 and 6, respectively. The mean reduction in central subfield macular thickness was 206 μm (95% CI, 157–255 μm) and 146 μm (95% CI, 98–195 μm) at months 2 and 6, respectively. Conclusions Dexamethasone implant is a functionally and anatomically effective treatment for DME in real-life practice. Qualitative anatomic recurrence seems to be an early sign of quantitative anatomic and functional recurrence. Further studies should demonstrate if early retreatment at the qualitative anatomic recurrence stage could better protect patient visual function.