Incidence and risk factors for neovascular AMD in the fellow eye in the Comparison of AMD Treatment Trials (CATT) Follow-up Study

Abstract

Purpose : To describe incidence and risk factors for neovascular age-related macular degeneration (nAMD) in the second (fellow) eye among patients enrolled in the Comparison of AMD Treatments Trials (CATT) with unilateral nAMD.

Methods : CATT participants were randomly assigned to receive ranibizumab or bevacizumab and to 1 of 3 dosing regimens in the eye with nAMD at baseline. After two years, patients were released from the clinical trial protocol and were recalled for examination at 5 years. At baseline, masked readers evaluated fundus morphology on color photographs & fluorescein angiography and fluid in & thickness of the retina on optical coherence tomography (OCT). Incident nAMD was identified during clinical examination by CATT ophthalmologists. A subset of patients provided blood samples and had genotyping for SNPs previously associated with AMD. Incidence was estimated with Kaplan-Meier curves and risk factors evaluated with the Cox proportional hazards model to provide adjusted hazard ratios (aHRs) and 95% confidence intervals.

Results : Among 1185 CATT patients, 727 were at risk of developing nAMD in the fellow eye. The 5-year cumulative incidence was 48%. Greater risk was associated with the AREDS risk score (aHR for score of 4 vs 2: 2.92 [1.19, 7.14]; p=0.01), presence of pseudodrusen (aHR for Yes vs No: 1.54 [1.15,2.0]; p=0.007); occult lesion type in the study eye (aHR for occult vs predominantly classic: 1.75 [1.20, 2.53]; p= 0.006); hemorrhage associated with the lesion in the study eye (>1 disc area vs None: 1.75 [1.20, 2.53]; p<0.001) and elevation of the retinal pigment epithelium on OCT in the study eye (Yes vs No: 1.79 [1.08, 2.96]; p=0.02) – see Table 1. There was no significant association with the drug administered during the first 2 years in CATT: (aHR for ranibizumab vs bevacizumab: 1.26 [0.96, 1.66]; p=0.09). No increased risk was associated with CFH, ARMS2, HTRA1, or C3 - see Table 2.

Conclusions : Over 5 years of follow-up, approximately half of CATT patients with unilateral nAMD at baseline developed nAMD in the fellow eye. Factors in the fellow eye (drusen, pigmentary changes, and pseudodrusen) and factors in the first affected eye (occult lesion, hemorrhage, and elevation of the retinal pigment epithelium) are associated with higher risk.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

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