Evaluation of Serum Endocan and Testosterone Levels in Male Patients with Prediabetes: A Cross-Sectional Clinical Study

<b>Background/Objectives:</b> This study aimed to investigate the relationship between serum endocan and total testosterone levels in male patients with prediabetes. <b>Materials and Methods:</b> This cross-sectional observational study included 37 men with prediabetes and 37 healthy male controls. In addition to routine laboratory tests, blood samples were collected to measure serum endocan levels using the enzyme-linked immunosorbent assay (ELISA), and total testosterone levels were analyzed using a chemiluminescence method. <b>Results:</b> Age did not differ significantly between the groups (<i>p</i> > 0.05). Body mass index (BMI), fasting plasma glucose (FPG), postprandial plasma glucose (PPG), insulin, HbA1c, and serum endocan levels were significantly higher in the prediabetes group (BMI: <i>p</i> = 0.003; FPG: <i>p</i> < 0.001; PPG: <i>p</i> = 0.019; insulin: <i>p</i> = 0.007; HbA1c: <i>p</i> < 0.001; endocan: <i>p</i> = 0.012). No significant difference was observed in testosterone levels between the groups (<i>p</i> = 0.228). <b>Conclusions:</b> Elevated serum endocan levels in individuals with prediabetes may reflect early endothelial dysfunction associated with glycemic dysregulation. These findings suggest that endocan may serve as an exploratory biomarker of early vascular alterations in prediabetes. However, further large-scale and prospective studies are warranted to clarify its clinical relevance and potential role in risk stratification and the prediction of microvascular complications.