Systemic and Ocular Predictive Factors in the Treatment of Diabetic Macular Edema with Bevacizumab

Background and Objectives: This study aimed to explore peripheral blood and OCT risk biomarkers that may modify the anatomical and functional response to intravitreal bevacizumab (IVB) treatment in diabetic macular edema (DME). Materials and Methods: The study included patients with non-proliferative diabetic retinopathy (NDR) who had not previously undergone laser photocoagulation or IVB. Data on demographics, hemogram, and biochemistry within one month before treatment were collected. Best corrected visual acuity (BCVA), intraocular pressure (IOP), and spectral-domain OCT (SD-OCT) measurements were recorded before and after three monthly IVB injections. OCT parameters included central macular thickness (CMT), inner and outer retinal thickness (IRT, ORT), ganglion cell layer thickness (GCT), and central choroidal thickness (CCT). Results: The study analyzed 48 eyes. Significant improvements were seen in BCVA (logMAR 0.44 to 0.18), while IOP increased slightly (15 to 17.5 mmHg). There were notable reductions in CMT, GCT, and IRT. Anatomical success (83.3%) was associated in univariate analysis with greater OCT improvement and higher white blood cell count (WBC) levels (p < 0.05). Central macular thickness decreased by 27% (from 427 to 312 μm), and visual acuity improved from 0.44 to 0.18 logMAR. In logistic regression analysis, factors associated with functional success (75%) included higher blood urea nitrogen (BUN) levels [OR 1.11 (95% CI: 1.03-1.21), p = 0.008], lower low-density lipoprotein (LDL) levels (p = 0.013), and lower baseline intraocular pressure (IOP) (p = 0.013). Conclusions: Intravitreal bevacizumab is effective in early diabetic macular edema. Elevated BUN and lower LDL levels may be associated with a favorable functional response to treatment.