Pseudodrusen and Incidence of Late Age-related Macular Degeneration (AMD) in Fellow Eyes in the Comparison of AMD Treatments Trials (CATT)

Abstract

Purpose : To evaluate the association of presence and type of pseudodrusen with incidence of late age-related macular degeneration (AMD) in fellow eyes of patients with unilateral neovascular AMD (nAMD).

Methods : Fellow eyes of CATT participants with neither nAMD nor geographic atrophy (GA) at baseline were assessed for presence and type (dot, ribbon, and confluent) of pseudodrusen using digital color fundus photographs viewed under full color, green channel, and blue channel; red free images; and fluorescein angiograms. Incidence of nAMD was based on clinical examination by retina specialists every 4 weeks through 2 years and reading center evaluation of images at Years 1 and 2. Incidence of GA was based on reading center evaluation of CFP and FA at Years 1 and 2. Associations of baseline pseudodrusen with incident nAMD, GA, and late AMD were summarized with adjusted risk ratios (aRRs) and their 95% confidence intervals (95% CIs) from multivariate Cox models with adjustment of covariates identified through backward stepwise selection.

Results : Among 620 fellow eyes at baseline, 176 (28.4%) had pseudodrusen. Within 2 years, nAMD occurred in 54 (30.7%) eyes with pseudodrusen and in 72 (16.2%) without pseudodrusen (aRR=2.1, P<0.0001); GA occurred in 27 (15.3%) eyes with pseudodrusen and in 37 (8.3%) without pseudodrusen (aRR=1.9, P=0.02); late AMD occurred in 73 (41.5%) eyes with pseudodrusen and in 101 (22.8%) without pseudodrusen (aRR=2.1, P<0.0001). Dot pseudodrusen (aRR=2.5, P<0.0001) were independently associated with nAMD, while confluent pseudodrusen (aRR=5.0, P=0.0006) were independently associated with GA (Table 1). Eyes with pseudodrusen had increased risk of late AMD irrespective of whether the Age-related Eye Diseases Study (AREDS) severity score was 2 (28.7% vs. 10.3%), 3 (34.9% vs. 13.7%), or 4 (50.5% vs. 32.0%) (Figure 1).

Conclusions : Among CATT participants, pseudodrusen were independently associated with a higher incidence of both nAMD and GA in the fellow eye. Dot pseudodrusen were associated with nAMD and confluent pseudodrusen were associated with GA. Pseudodrusen should be considered along with the AREDS severity score for predicting late AMD.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

Table 1. The association of baseline pseudodrusen with incidence of nAMD and GA in the fellow eye

 

Figure 1. K-M curves for the development of late AMD by baseline pseudodrusen and AREDS severity score