Abstract
Purpose: :
To characterize the percent of African American (AA) participants progressing on the Age–Related Eye Disease Study (AREDS) simple clinical scale and to advanced age–related macular degeneration (AMD).
Methods: :
The AREDS clinical scale for assessing 5–year risk of progression to advanced AMD (neovascular AMD or geographic atrophy involving the center of the macula) is based on two retinal characteristics (drusen size and retinal pigmentary abnormalities). The percent of AA participants progressing on the AREDS clinical scale and to advanced AMD are based on a cohort of 157 AA participants and compared to a cohort of 4095 non–AA participants enrolled in AREDS. Each cohort had a median of 5–years of follow–up with similar follow–up distributions.
Results: :
The median age at baseline for the AA participants was 66 years versus 69 for non–AA participants. The proportion of AA participants vs. non–AA participants at baseline on each of the 5 steps of the AREDS clinical scale (ranging from 0–4) was: 67% vs. 39%, 15% vs. 17%, 11% vs. 16%, 5% vs. 13% and 2% vs. 16% for each step respectively. Of the 157 AA participants, 2 (1.3%) had developed advanced AMD by 5–years. In the full AREDS cohort, the expected 5–year progression rate to advanced AMD for steps 2–4 were 12%, 25% and 50% respectively. Although the number of AA participants in each of the AREDS clinical scale steps was relatively low, the observed proportion progressing to advanced AMD by 5 years were 6% (1/17 participants), 13% (1/ 8) and 0% (0/3), for steps 2 to 4 respectively. For participants at the lower end of the scale at baseline, where probability of progression to advanced AMD is low, the proportions progressing at least one step on the clinical severity scale by the 5–year visit for AA participants and non–AA participants for steps 0 – 2 were 13% vs. 22%, 4% vs. 31% and 18% vs. 44%, respectively.
Conclusions: :
The proportion of AA participants progressing to either advanced AMD or along the clinical AMD severity scale, is observed to be considerably lower that the proportion of non–AA participants progressing.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: natural history • drusen