Spectral-Domain OCT Analysis of Risk Factors for Macular Atrophy Development in the HARBOR Study for Neovascular Age-Related Macular Degeneration

Purpose: To identify baseline risk factors for macular atrophy (MA) development in HARBOR via a longitudinal assessment of monthly spectral-domain (SD)-OCT scans. Previous analyses of MA in HARBOR examined data from color fundus photography (CFP) and fluorescein angiography (FA). Design: Retrospective, post hoc analysis of SD-OCT images from HARBOR (ClinicalTrials.gov identifier, NCT00891735), a phase 3, multicenter, prospective, randomized, double-blind, active treatment–controlled clinical trial. Participants: Patients (N = 1097) with subfoveal choroidal neovascularization secondary to neovascular age-related macular degeneration (nAMD) treated with intravitreal ranibizumab 0.5 mg monthly (n = 275), 0.5 mg pro re nata (PRN) after 3 loading doses (n = 275), 2.0 mg monthly (n = 274), or 2.0 mg PRN (n = 273). Methods: Evaluable SD-OCT macular cube scans from patients with 24 months of follow-up (N = 941) were examined monthly from baseline to month 24 by masked reading center–trained graders. Atrophy diagnosis criteria were consistent with those proposed by the Classification of Atrophy Meetings (CAM) group: hypertransmission of light into the choroid, loss of retinal pigment epithelium, and loss of outer retinal layers. Multivariable proportional hazards regression was performed for time to atrophy development. Main Outcome Measures: Risk factors for MA as determined by time to MA development over 24 months of treatment. Results: Baseline risk factors for MA were confirmed from prior analyses that used CFP and FA data: absence of subretinal fluid, presence of intraretinal cysts, presence of Type 3 neovascularization, and presence of atrophy in the fellow eye. This analysis of SD-OCT data identified new baseline risk factors for MA: higher central drusen volume, lower choroidal thickness, presence of nascent atrophy, presence of reticular pseudodrusen, and increased central foveal thickness. Ranibizumab treatment regimen and dose level were not found to be risk factors for MA development. Conclusions: In this analysis of a major nAMD trial using CAM atrophy criteria, new baseline risk factors for MA development were identified using an SD-OCT dataset. Risk factors for MA development identified by prior analyses were confirmed. Monthly treatment with ranibizumab 0.5 mg was not found to be a risk factor for MA development over 24 months.