Optical Coherence Tomography-Based Grading of Diabetic Macular Edema Is Associated with Systemic Inflammatory Indices and Imaging Biomarkers

Abstract

Introduction: Objectives of the study were to investigate the correlation between OCT-based grading of diabetic macular edema (DME) and systemic inflammatory indices, imaging biomarkers, and early anti-VEGF treatment response. Methods: A total of 111 eyes from 111 patients with DME treated with intravitreous anti-VEGF therapy for 3 consecutive months every month were enrolled in this retrospective study. According to a protocol termed "TCED", DME was divided into early, progressive, severe and atrophic stages. The best-corrected visual acuity (BCVA), subretinal fluid (SRF) and the number of hyperreflective foci (HRF) in the whole retinal layers were analyzed at baseline and three months after the first injection. Peripheral blood inflammatory indices were calculated, including neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet (PLT)-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII) and C-reactive protein (CRP). Statistical analysis were performed to compare the visual and anatomical results and evaluate HRF and SRF in different stages of DME before and after treatment. Results: There were significant differences in systemic inflammatory indices among the four groups, including NLR, PLR, MLR, SII and CRP ( all P < 0.05). The CRP, NLR, PLR, MLR, and SII were significantly higher in the atrophic stage compared to the advanced stage (all P < 0.05). Conversely, the CRP, NLR, PLR, MLR, and SII were significantly lower in the advanced stage compared to the early stage (all P < 0.05). Except for the atrophic stage, BCVA and CRT were significantly improved after treatment in early, advanced and severe stages (all P < 0.05), especially in the severe stage. The decline in the proportion of SRF and HRF ≥ 20 were the most significant in the advanced stage after anti-VEGF treatment (P < 0.001, P = 0.016), but not in the early and severe stages (all P > 0.05). Conclusion: Systemic inflammatory indices and the decline in the proportion of SRF and HRF ≥ 20 were closely associated with different stages of DME based on "TCED". Meanwhile, the "TCED" grading system can predict visual and anatomical prognosis of DME after anti-VEGF treatment, which may be a biomarker for identifying risk stratification and management of DME.