Association between peripheral blood biomarkers and diabetic macular edema

To investigate the association between peripheral blood biomarkers and DME severity.

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.

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).

DME is characterized by reduced RBC measures and elevated inflammatory indices. Decreased RBC measures could serve as potential markers of DME severity.