Association between peripheral blood biomarkers and diabetic macular edema.

AIM: To investigate the association between peripheral blood biomarkers and DME severity. METHODS: This cross-sectional study included 227 consecutive patients (305 eyes) with DME and 94 controls (94 eyes). DME was classified into early, advanced, and severe stages based on spectral-domain optical coherence tomography. Peripheral blood samples were analyzed, and the association between peripheral blood biomarkers and DME severity was evaluated using generalized estimating equations. RESULTS: Compared with the control group, patients with DME exhibited significantly lower values in red blood cell (RBC) count (P < 0.001), hemoglobin (P < 0.001) and hematocrit (P < 0.001), as well as significantly higher values in white blood cell count (P < 0.001), neutrophil count (P < 0.001), monocyte count (P < 0.001), fibrinogen level (P < 0.001), D-dimer level (P = 0.015), neutrophil-to-lymphocyte ratio (P < 0.001), and monocyte-to-lymphocyte ratio (P < 0.001). Moreover, advanced or severe DME was associated with RBC count (10^12/L) (OR (95% CI) = 0.49 (0.288, 0.834), P = 0.009), hemoglobin (g/L) (OR (95% CI) = 0.978 (0.959, 0.996), P = 0.02), and hematocrit (%) (OR (95% CI) = 0.919 (0.859, 0.985), P = 0.016). CONCLUSIONS: DME is characterized by reduced RBC measures and elevated inflammatory indices. Decreased RBC measures could serve as potential markers of DME severity.