Abstract
Purpose :
The Age-Related Eye Disease Study (AREDS) age-related macular degeneration (AMD) scale was designed to allow precise description of the presence and progression of AMD. We examined the prognostic significance of step changes on the AMD scale in predicting visual acuity (VA) loss and late AMD.
Methods :
The AREDS clinical trial (1992-2001) demonstrated a protective effect of high-dose antioxidants and minerals on risk of late AMD. Baseline and annual fundus photographs were graded at the University of Wisconsin reading center by masked graders using a standardized protocol; the AREDS scale (for non-late AMD: scores 1-9 with increasing drusen area and pigment changes) was determined for each eye. Late AMD was defined as photographic grading of neovascular (NV) AMD or central geographic atrophy (CGA) or history of treatment for NV AMD. Early progression risk factors were defined as 1-, 2-, or 3-step increases in AMD scale score in the first 2 years after randomization. Outcomes evaluated were 2-line and 3-line VA loss and development of late AMD, from 2 years until the end of follow-up. SAS proc PHREG (version 9.4) was used to obtain estimates of hazard ratios (HRs), adjusting for correlation between eyes.
Results :
Of 4757 participants enrolled in AREDS, 3946 were free of late AMD in both eyes at baseline (mean age, 68.3 y; 56.4% female). During follow-up, 43.6% of eyes experienced a ≧2-line VA loss; 25.6% had a ≧3-line VA loss, and 13.2% developed late AMD. We found that early progression was significantly associated with risk of subsequent 2- and 3-line VA loss (HRs ranged from 1.57 (95% CI, 1.45-1.70) to 3.13 (95% CI, 2.52-3.88) and with risk of late AMD (HRs ranged from 3.44 (3.02-3.92) to 8.98 (7.15-11.29). Baseline AMD score was also significantly associated with 2- and 3-line VA loss and development of late AMD. Because of significant interaction between early progression and baseline AMD scores, we stratified analyses by baseline AMD score (Table). Risk of 2- or 3-line VA loss was significantly associated with early progression for nearly all baseline AMD scores.
Conclusions :
Early progression in AMD scale score in AREDS was significantly associated with subsequent risk of VA loss and with development of late AMD, independent of baseline AMD score. The AREDS scale for AMD may be a useful prognostic tool for ongoing clinical trials.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.