Serum inflammation biomarkers level in cystoid and diffuse diabetic macular edema

To assess serum inflammatory biomarker levels in patients with different subtypes of diabetic macular edema (DME).

We retrospectively analyzed 50 eyes from 37 treatment-naïve DME patients who underwent intravitreal injection therapy between June and December 2023. Based on the morphological characteristics of macular edema in optical coherence tomography (OCT), the eyes were categorized into the cystoid macular edema (CME) group (n = 25) and diffuse retinal thickening (DRT) group (n = 25). Additionally, 25 eyes with diabetes retinopathy but without DME served as the control group. Comprehensive clinical data were reviewed, including best-corrected visual acuity (BCVA), central macular thickness (CMT), macular cube volume (VOL) and hematological examination. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) were calculated.

NLR and SII levels were significantly higher in the CME group compared to the DRT group and control group (all P < 0.01). The optimal ROC cutoff value of NLR for CME was 2.27, with 88.0% sensitivity and 68.0% specificity. The optimal ROC cutoff value of SII for CME was 447.33, with 84.0% sensitivity and 60.0% specificity. After initial intravitreal injection therapy, BCVA and VOL significantly improved in each group (all P < 0.01). However, no significant correlation was found between systemic inflammatory marker levels and postoperative changes in BCVA, CMT and VOL (all P > 0.05).

Our study suggests that elevated NLR and SII levels are significantly associated with CME. Elevated serum inflammatory biomarkers may indicate a higher incidence of CME in these patients.