Baseline OCT microstructural burden associated with persistent central thickening after intravitreal treatment for diabetic macular edema

Abstract Background Central subfield thickness (CST) quantifies diabetic macular edema (DME) but does not describe accompanying retinal morphology. We examined whether baseline optical coherence tomography (OCT) microstructural burden was associated with persistent central thickening following intravitreal treatment, with baseline CST taken into account. Methods This single-center retrospective cohort included 138 eyes of 76 patients treated with anti-vascular endothelial growth factor (anti-VEGF) agents or dexamethasone implants. An unweighted 0–4 score assigned one point for foveal eversion, more than 30 hyperreflective foci, vitreomacular interface abnormality, and ellipsoid zone disruption. Persistent central thickening was defined as CST ≥ 300 μm at month 3 (M3; 45–135 days; primary outcome) or month 6 (M6; 135–225 days; key secondary outcome). Patient-clustered logistic generalized estimating equations estimated adjusted odds ratios (ORs) per point, controlling for age, sex, baseline CST, and baseline logarithm of the minimum angle of resolution (logMAR) visual acuity; CST was analyzed continuously. Results Persistent thickening occurred in 88 of 118 eyes (74.6%) at M3 and 64 of 92 eyes (69.6%) at M6. Rates rose stepwise across score groups and exceeded 90% for scores of 3–4 at both time points. Each score point was associated with persistent thickening at M3 (adjusted OR, 2.30; 95% confidence interval [CI], 1.41–3.74) and M6 (adjusted OR, 2.42; 95% CI, 1.39–4.22). At M6, each point was associated with 39.98 μm higher CST (95% CI, 8.33–71.64), whereas the M3 estimate was nonsignificant. Sensitivity analyses adjusting for treatment type and repeatedly selecting one eye per patient were directionally consistent. Conclusions In this exploratory analysis, baseline OCT microstructural burden was associated with persistent central thickening at 3 and 6 months after baseline CST was taken into account. The score provides a concise, interpretable summary of the accompanying structural abnormalities.