Risk of Geographic Atrophy in the Comparison of Age-related Macular Degeneration Treatments Trials

Purpose: To describe risk factors for geographic atrophy (GA) in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT). Design: Cohort within a randomized clinical trial. Participants: We analyzed 1024 CATT patients with no GA visible on color fundus photographs (CFPs) and/or fluorescein angiograms (FAs) at enrollment. Methods: Eyes were assigned to ranibizumab (0.5 mg) or bevacizumab (1.25 mg) treatment and to a 2-year monthly or pro re nata (PRN) injection regimen, or monthly injections for 1 year and PRN for 1 year. Demographic, genetic, and baseline ocular characteristics and lesion features of CFP/FA and optical coherence tomography (OCT) were evaluated as risk factors for GA through 2 years of follow-up. Time-dependent Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs). Main Outcome Measures: Development of GA. Results: By 2 years, GA developed in 187 of 1024 patients (18.3%). Baseline risk factors for GA development included baseline visual acuity (VA) <= 20/200 (aHR, 2.65; 95% confidence interval [CI], 1.43-4.93), retinal angiomatous proliferation (RAP; aHR, 1.69; 95% CI, 1.16-2.47), GA in the fellow eye (aHR, 2.07; 95% CI, 1.40-3.08), and intraretinal fluid at the foveal center (aHR, 2.10; 95% CI, 1.34-3.31). Baseline factors associated with lower risk for GA development included blocked fluorescence (aHR, 0.49; 95% CI, 0.29-0.82), OCT measurements of subretinal fluid thickness of >25 mu (aHR, 0.52; 95% CI, 0.35-0.78), subretinal tissue complex thickness of >275 compared with <= 75 mu (aHR, 0.31; 95% CI, 0.19-0.50), and vitreomacular attachment (aHR, 0.55; 95% CI, 0.31-0.97). Ranibizumab compared with bevacizumab had a higher risk (aHR, 1.43; 95% CI, 1.06-1.93), and monthly dosing had a higher risk (aHR, 1.59; 95% CI, 1.17-2.16) than PRN dosing. There were no strong associations between development of GA and the presence of risk alleles for CFH, ARMS 2, HTRA1, C3, or TLR3. Conclusions: Approximately one fifth of CATT patients developed GA within 2 years of treatment. Independent baseline risk factors included poor VA, RAP, foveal intraretinal fluid, monthly dosing, and treatment with ranibizumab. Anti-vascular endothelial growth factor therapy may have a role in the development of GA. (C) 2014 by the American Academy of Ophthalmology.