Correlation of functional and anatomical improvement following treatment for Diabetic Macular Edema: a post-hoc analysis

Abstract

Purpose : Intravitreal Anti-Vascular Endothelial Growth Factor (Anti-VEGF) has become the mainstay of treatment for Diabetic Macular Edema (DME) and the assessment of best corrected visual acuity (BCVA) using the Early Treatment of Diabetic Retinopathy Study (ETDRS) is the widely agreed upon measure for functional improvement. This post-hoc analysis at month 6 endpoint of Ranibizumab for Edema of the mAcula in Diabetes — Protocol 3 (READ-3) seeks to study the trend and association of anatomical and functional improvement in patients successfully treated for DME.

Methods : Trends in BCVA and central retinal thickness (CRT) changes of 21 eyes from 21 participants with CRT lower than 250µm on time-domain optical coherence tomography (TD-OCT) at month 6 were analyzed using Stata 15.1 (StataCorp LLC, College Station, TX, USA). Patients in the READ-3 study received six mandatory monthly injections. Starting at month 6, patients received injections based on visualization of edema on OCT according to the retreatment criteria. This study analyzed the lag between anatomical and functional changes, as well as the injection-free duration of patients treated for DME. The changes in BCVA (minimum 4 letters on ETDRS chart) and CRT (30µm on TD-OCT) on monthly follow-ups were analyzed using descriptive statistics.

Results : The mean age of the study participants was 65.6 ± 10.7 years. A decrease in CRT of 30 µm from baseline after monthly IVT injection of ranibizumab was accompanied by improvement in 4 letters of BCVA in 9 patients (42.9%). Majority of the remaining patients, 8 (38.1%), experienced a lag of 1 month in BCVA improvement. Whereas a median lag of 4 months (2-5 months) was seen in 4 patients. During the treat and extend period, changes in BCVA and CRT coincided in 5 patients, while worsening of BCVA preceded increase in CRT in 5 patients by a median of 3 months (lag time range 1-12 months). CRT changes preceded BCVA changes in 4 cases, 5 patients were administered therapy before CRT and BCVA changes could be observed.

Conclusions : In a subset of patients with DME, BCVA may be used independently to monitor progression of disease thus reducing our reliance on OCT imaging for clinical decision making.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Graphical representation of the mean change in BCVA and CRT for the first 6 months of the study.