Factors Affecting Visual Outcomes in Patients With Diabetic Macular Edema Treated With Ranibizumab

R Channa; R Sophie; AA Khwaja; DV Do; G Hafiz; QD Nguyen; PA Campochiaro

Disclosures

Eye. 2014;28(3):269-278. 

In This Article

Abstract and Introduction

Abstract

Purpose: To identify factors associated with visual outcomes in patients with diabetic macular edema (DME) treated with ranibizumab (RBZ) in the Ranibizumab for Edema of the mAcula in Diabetes—Protocol 2 (READ-2) Study.

Patients and methods: Optical coherence tomography scans, fundus photographs, and fluorescein angiograms (FAs) were graded and along with baseline characteristics were correlated with month (M) 24 visual outcome of best-corrected visual acuity (BCVA) ≤20/100 (poor outcome) vs >20/100 (better outcome).

Results: Of 101 patients with a M20 visit or beyond, 27 (27%) had BCVA ≤20/100. Comparison of patients with or without poor outcome showed mean baseline BCVA of 16.8 letters (20/125) in the former compared with 30.4 letters (20/63; P<0.001). Mean change in BCVA between baseline and M24 was −2.6 letters in the poor outcome group compared with +9.8 letters (P<0.001). Foveal thickness (FTH) at M24 was 374.1 μm in the poor outcome group compared with 268.8 μm (P<0.01), a difference driven by 14 patients with mean FTH of 450.3 μm. Foveal atrophy occurred in 65% (11/17) in the poor outcome group compared with 17%(12/71, P=0.001). Persistent edema was noted in 52% (14/27) of patients with poor outcome. Laser scars near foveal center were significantly more common in patients with poor outcome who did not have edema vs those who did (78% (7/9) vs 23% (3/13) P=0.03).

Conclusion: Poor baseline BCVA (≤20/125) in DME patients predicts poor visual outcome (≤20/100) after 2 years of treatment with RBZ and/or focal/grid laser, often due to foveal atrophy and/or persistent edema.

Introduction

Diabetic retinopathy is a prevalent cause of reduced vision, mostly due to diabetic macular edema (DME).[1] Although the pathogenesis of DME is not completely understood, recent studies have demonstrated that vascular endothelial growth factor (VEGF) has a major role.[2,3] The first study to clearly implicate VEGF was the Ranibizumab for Edema of the mAcula in Diabetes (READ) trial, which demonstrated a mean improvement in best-corrected visual acuity (BCVA) of 12.3 letters in patients with chronic DME given five intraocular injections of 0.5 mg of ranibizumab (RBZ) over the course of 7 months.[2] This led to the READ-2 study, in which patients with DME were randomized to receive intraocular injections of RBZ (RBZ group), focal/grid laser (laser group), or a combination of RBZ and focal/grid laser (RBZ+laser group). At the month (M) 6 primary end point, RBZ patients who were treated with intraocular injections of 0.5 mg of RBZ at baseline and months 1, 3, and 5 showed a mean improvement in BCVA of 7.2 letters compared with −0.4 letters in the laser group (P=0.01), whereas RBZ+laser patients had a mean improvement of 3.8 letters (P=0.08).[3] After the primary end point, patients in the RBZ group were seen every 2 months and if foveal thickness (FTH, center subfield thickness) was 250 μm or greater, with time domain optical coherence tomography (OCT), they were treated with 0.5 mg RBZ. Patients in the laser group were seen every 2 months and if FTH was 250 μm or greater, they could be treated with laser or RBZ. Patients in RBZ+laser group were seen every 3 months and if FTH was 250 μm or greater, they could receive laser plus RBZ or RBZ alone. At M24, the mean improvement in BCVA letters was 7.7, 5.1, and 6.8 in RBZ, laser, and RBZ+laser groups.[4] Some patients had an outstanding outcome, with 45, 44, and 35% of patients having a M24 BCVA ≥20/40, whereas others fared less well. In this study, we sought to determine why some patients in the READ-2 study had a suboptimal visual outcome.

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