Visual and Anatomical Outcomes of a Single Intravitreal Dexamethasone in Diabetic Macular Edema: An 8 Year Real-World Study

Importance: Diabetic macular edema (DME) is a major cause of vision loss in patients with diabetes mellitus. Intravitreal dexamethasone is a treatment option for patients unsuitable for or non-responsive to anti-angiogenic agents. Objective: To quantify visual and anatomical outcomes from an initial intravitreal dexamethasone injection over the expected 6-month period of dexamethasone release by the implant. Design and enrolment: This is a retrospective cohort study using electronic medical records of patients reviewed between 1 January 2012 and 1 April 2022. Setting: A tertiary eye-care center in London, United Kingdom; Moorfields Eye Hospital National Healthcare System Foundation Trust. Participants: The cohort comprised 418 adult patients with DME who received an initial treatment of 700 & mu;g intravitreal dexamethasone in the study period. Of these, 240 patients met the inclusion criteria of & GE;2 hospital visits following initial injection (& GE;1 beyond 6 months) and no previous ocular corticosteroid treatment or missing assessment at baseline. Exposure(s): Intravitreal dexamethasone implant (700 & mu;g). Main Outcome(s) and Measure(s): Probability of a positive visual outcome, defined as & GE;5 or & GE;10 Early Treatment Diabetic Retinopathy Study (ETDRS)-letter gain after treatment when compared to baseline (Kaplan-Meier models). Results: From the initial intravitreal dexamethasone injection alone, we observed a >75% chance of gaining & GE;5 ETDRS letters and >50% chance of gaining & GE;10 ETDRS letters within 6 months. There was less than a 50% chance of sustaining either positive visual outcome beyond 4 months. Conclusions and Relevance: Most patients can be expected to have a positive visual outcome following an initial injection of dexamethasone implants that subsides within 4 months. Real-world re-treatment was observed to be delayed until after visual benefits were lost in half of the cohort. Further research will be needed to study the effects of delays in re-treatment.