Abstract
Purpose::
To identify baseline participant and ocular risk factors for choroidal neovascularization (CNV) and geographic atrophy (GA) in CAPT participants.
Methods::
1052 participants with >= 10 large drusen (>125µ) and VA >= 20/40 in each eye participated with one eye randomly assigned to laser treatment and the contralateral eye to observation.At baseline, participants provided demographic information, history of diabetes mellitus and cigarette smoking, use of anti-hypertension medications. Blood pressure (BP) was measured. Trained readers evaluated color photographs for baseline drusen characteristics and pigmentary abnormalities. During follow-up, readers identified CNV (leakage on fluorescein angiography) and endpoint GA (> 1 DA combined area on color photographs). Estimates of relative risks (RR) and 95% confidence intervals (95% CI) were obtained from univariate and multivariate survival analysis of observed and treated eyes, considered separately and combined with treatment as a covariate.
Results::
CNV developed in 141 treated eyes and 141 observed eyes. Statistically significant risk factors in the multivariate model for observed eyes were current smoking vs. never [1.89 (1.03, 3.47)] and definite hypertension vs. none [1.55 (1.07, 2.25)]. For treated eyes, older age [5.98 (1.66, 15.0) for >79 vs. <60 yrs], current smoking vs. never [1.95 (1.00, 3.81)], and focal hyperpigmentation >=250u vs. none [2.25 (1.34, 3.79)] were significant risk factors. When both groups were combined, older age, current smoking, hypertension, and focal hyperpigmentation were significant risk factors.GA developed in 74 treated eyes and 78 observed eyes. Statistically significant risk factors in the multivariate model for observed eyes were older age [1.59 (1.19, 2.12) for every 10 years increase], greater retinal area covered by drusen (>63µ) 8.44 (4.31, 16.5) for >25% vs. <10%], retinal pigment epithelium (RPE) depigmentation vs. none [2.63 (1.27, 5.44)], and focal hyperpigmenation [9.49 (3.41, 26.4) for >=250µ vs. none]. Similar associations were seen in the analyses for treated eyes only and for both eyes combined.
Conclusions::
Among CAPT participants with >=10 large drusen in each eye, risk factors for CNV differed from those for GA. Cigarette smoking and hypertension were associated with CNV only, while percent of retinal area covered by drusen and RPE depigmentation were associated with GA only.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: risk factor assessment • retinal neovascularization