Exploratory analysis to determine if geographic atrophy in eyes that later develop exudative AMD grow at a slower rate in AREDS2 participants

Abstract

Purpose : To determine if growth of geographic atrophy (GA) area is influenced by subsequent development of exudative age-related macular degeneration (EAMD) in AREDS2 participants.

Methods : Study eyes that had either GA at baseline (pre-existing GA, PGA) or developed GA during the study (incident GA, IGA) without prior or concurrent EAMD were identified. Eyes that developed EAMD following GA onset were also included if the development of EAMD occurred at least 2 years following GA onset. Mixed-model regression of the GA area and square root transformed GA area growth rates were computed for all included eyes prior to EAMD development. Baseline participant characteristics and imaging features were also compared.

Results : Study eyes (n=1213) comprised both PGA (n=456) and IGA (757) eyes, and a total of 136 (11.2%) developed EAMD during the course of the study. In comparison of eyes that did vs those that did not develop EAMD, baseline GA area, central GA involvement, GA configuration, sex, and smoking history were similar while those that did not develop EAMD were associated with slightly younger age (74.7 vs 76.3 yrs, p=0.02). Average follow-up for those eyes that did not develop EAMD eyes was also longer than those that did develop EAMD, 3.1 vs 1.9 yrs. After adjusting for age, sex, and baseline GA size, the combined cohort of PGA and IGA eyes revealed similar GA area growth (1.29 vs 1.10 mm²/yr, p=0.127) and square root transformed area growth (0.28 vs 0.27 mm/yr, p=0.634). Subgroup analyses of PGA eyes showed also no significant difference in the GA growth between the eyes that did or did not develop EAMD (1.44 vs 1.39 mm²/yr and 0.29 vs 0.31 mm/yr, p= 0.82 and 0.57, resp). However, similar comparison in the subgroup of IGA eyes revealed significantly slower GA area growth (1.13 mm²/yr vs 0.62 mm²/yr, p=0.004) and square root transformed area growth (0.29 mm/yr vs 0.20 mm/yr, p=0.04) in eyes that developed EAMD. The difference was still significant after adjusting for smoking history.

Conclusions : The primary analyses of the GA growth rates in the combined cohort of PGA and IGA eyes showed no difference between those eyes with or without development of EAMD. There was a significant difference found only in the subgroup IGA eyes. This hypothesis may warrant further evaluation in studies with longer follow-up and larger sample size.

This is a 2020 ARVO Annual Meeting abstract.