Evaluation of C-Reactive Protein/Albumin Ratio in Diabetic Retinopathy Patients

<b>Purpose:</b> This study aimed to investigate the relationship between the C-reactive protein/albumin (CRP/albumin) ratio and disease severity in diabetic retinopathy (DR) patients and to evaluate the potential of CRP/albumin as a clinical biomarker for inflammation and DR progression. <b>Methods:</b> This single-center, prospective, cross-sectional study included 158 DR patients and 150 healthy controls. Clinical, ophthalmologic, and laboratory evaluations were performed, including best-corrected visual acuity, optical coherence tomography, and measurements of inflammatory and glycemic markers. CRP/albumin ratios were calculated, and their relationships with DR severity were assessed. Receiver operating characteristic (ROC) analysis was performed to evaluate the predictive performance of CRP/albumin. <b>Results:</b> Before treatment, CRP/Alb ratios and other inflammatory markers, including NLR, MLR, PLR, and SII, were significantly elevated in DR patients compared to controls. Following treatment, CRP/albumin ratios decreased markedly from 0.14 ± 0.1 to 0.04 ± 0.04 (<i>p</i> < 0.001), aligning with improvements in retinal thickness (OCT: 269.2 ± 17.5 µm) and HbA1c levels (6.9 ± 1.2%). CRP levels decreased from 5.8 ± 3.2 mg/L to 1.5 ± 1.4 mg/L, while NLR dropped from 2.5 ± 1.1 to 1.29 ± 0.8 (<i>p</i> < 0.001). Significant reductions were also observed in PLR (169.6 ± 62.2 to 128.2 ± 54.3) and SII (743.0 ± 427 to 230.8 ± 187). ROC analysis revealed an AUC of 0.963 for CRP/albumin, indicating high predictive accuracy for DR severity with 95% sensitivity and 90% specificity at a cutoff of 0.052. <b>Conclusions:</b> The CRP/albumin ratio is a significant biomarker for inflammation and disease progression in DR. The observed reductions in inflammatory markers post-treatment highlight the importance of inflammation control in DR management.