Purpose:
Glaucoma and age-related macular degeneration (AMD) are leading causes of blindness among older adults; however, glaucoma incidence among patients diagnosed or at risk for AMD is unknown. Here, we identify the 5- and 10-year glaucoma incidence among subjects enrolled in the AREDS study, a longitudinal cohort of older adults involved in a randomized clinical trial in which none had glaucoma at enrollment.
Methods:
The publicly available AREDS database was used in analysis in which the four-category AMD classification (Cat1 - Cat4) was defined based on the size and extent of drusen, the presence of manifestations of AMD, and visual acuity (ie, AMD status ranged from no evidence of AMD in either eye to relatively severe disease). Study procedures required patients with intraocular pressures >=26 mm Hg or a reason to suspect glaucoma (eg, hx diagnosis or past/present medication use to control pressure, or disc/nerve fiber defects suggestive of glaucoma) to have an absence of perimetric glaucomatous visual field defect documented within 6 months prior to AREDS enrollment. Glaucoma was identified through self report, in which subjects were queried annually as part of a detailed protocol.
Results:
2260 of 4116 (54.9%) enrolled subjects were female; race was self-reported as white among 3941 (95.8%) subjects and black among 148 (3.6%) subjects; median age at enrollment was 69.4 years (SD ± 5.1); and AMD classification at baseline was as follows: 976 (23.1%) Cat1, 897 (21.8%) Cat2, 1391 (33.8%) Cat3, and 852 (20.7%) Cat4. Self-reported glaucoma incidence was 5.2% (211 of 3873) through five years, and 8.5% (349 of 3736) through ten years. Blacks were statistically more likely to develop glaucoma at both five and ten years (5 yr OR: 2.2, 95% CI: 1.3 - 3.8; 10 yr OR: 2.1; 95% CI: 1.3 - 3.3). Subjects with incident glaucoma at five and ten years were significantly older at enrollment (10 yrs: 70.1 vs. 69.4 yrs, t-test, p = 0.008). Crude analysis did not identify a significant association between gender, baseline AMD status, treatment category or final AMD status and 5- and 10-year glaucoma incidence (10 yr results: Chi-square, p = 0.64, p = 0.51, p = 0.55 and p = 0.58, respectively).
Conclusions:
A sizeable number of subjects developed glaucoma in the AREDS Study, and factors associated with disease are consistent with generally accepted risk factors. This detailed dataset, which includes demographic, clinical, genetic and nutritional data, provides substantial research opportunities to examine glaucoma risk factors through secondary analyses using advanced longitudinal data analysis methods.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • aging • age-related macular degeneration