Subfoveal choroidal thickness predicts macular atrophy in age-related macular degeneration: results from the TREX-AMD trial

Background: Our purpose was to evaluate the relationship between subfoveal choroidal thickness (SCT) and development of macular atrophy (MA) in eyes with age-related macular degeneration (AMD). Methods: This was a prospective, multicenter study. Sixty participants (120 eyes) in the TREX-AMD trial (NCT01648292) with treatment-naïve neovascular AMD (NVAMD) in at least one eye were included. SCT was measured by certified reading center graders at baseline using spectral domain optical coherence tomography (SDOCT). The baseline SCT was correlated with the presence of MA at baseline and development of incident MA by month 18. Generalized estimating equations were used to account for information from both eyes. Results: Baseline SCT in eyes with MA was statistically significantly less than in those without MA in both the dry AMD (DAMD) (P = 0.04) and NVAMD (P = 0.01) groups. Comparison of baseline SCT between MA developers and non-MA developers revealed a statistically significant difference (P = 0.03). Receiver operating characteristic curve (ROC) analysis showed the cut-off threshold of SCT for predicting the development of MA in cases without MA at baseline was 124 μm (AUC = 0.772; Sensitivity = 0.923; Specificity = 0.5). Among eyes without MA at baseline, those with baseline SCT ≤124 μm were 4.3 times more likely to develop MA (Odds ratio: 4.3, 95% confidence interval: 1.6–12, P = 0.005) than those with baseline SCT >124 μm. Conclusions: Eyes with AMD and MA had less SCT than those without MA. Eyes with less baseline SCT also appear to be at higher risk to develop MA within 18 months.