The usefulness of systemic inflammatory markers as diagnostic indicators of the pathogenesis of diabetic macular edema

Abstract

Purpose: To investigate the usefulness of systemic inflammatory markers [i.e., white blood cell and platelet counts, mean platelet volume, and their ratios] as diagnostic markers of the pathogenesis of diabetic macular edema. Methods: The study cohort included 80 diabetic macular edema patients (40 with diabetic retinopathy and 40 without) and 40 healthy age- and sex-matched controls. Neutrophil, lymphocyte, monocyte, and platelet counts, and the mean platelet volume were determined from peripheral blood samples, and the monocyte/lymphocyte, platelet/lymphocyte, and mean platelet volume/lymphocyte, and neutrophil/lymphocyte ratios were calculated and compared among groups. Results: The mean neutrophil/lymphocyte ratio of the diabetic macular edema and non-diabetic macular edema groups was higher than that of the control group, and the value of the diabetic macular edema group was higher than that of the non-diabetic macular edema group (p<0.001 in diabetic macular edema vs. control, p=0.04 in non-diabetic macular edema vs. control, and p=0.03 in diabetic macular edema vs. non-diabetic macular edema). A neutrophil/lymphocyte cutoff value of >= 2.26 was identified as an indicator of the pathogenesis of diabetic macular edema with a sensitivity of 85% and specificity of 74%. The mean platelet volume of the diabetic macular edema group was higher than those of the non-diabetic macular edema and control groups, while those of the non-diabetic macular edema and control groups were similar (diabetic macular edema vs. non-diabetic macular edema, p=0.08; diabetic macular edema vs. control, p=0.02; and non-diabetic macular edema vs. control, p=0.78). All other parameters were similar between groups (all p>0.05). Conclusion: The neutrophil/lymphocyte ratio and mean platelet volume of the diabetic macular edema group were higher than those of the non-diabetic macular edema and control groups. A neutrophil/lymphocyte ratio cutoff value of >= 2.26 was identified as an indicator of the pathogenesis of diabetic macular edema with high sensitivity and specificity. Moreover, the neutrophil/ lymphocyte ratio of the non-diabetic macular edema group was higher than that of the control group.