Glycosylated Serum Protein May Improve Our Ability to Predict Endothelial and Erectile Dysfunction in Nonorganic Patients

Abstract

Early prediction of erectile dysfunction (ED) is critical in the treatment of impotence. Underlying pathogenesis may be the reason for ED without organic causes in young men. We evaluated the early predictive value of glycosylated serum protein (GSP) in young patients whose ED was diagnosed as "nonorganic" in origin according to general criteria. A total of 150 young men with ED and 27 healthy men without ED were evaluated, including International Index of Erectile Function-5 (IIEF-5), causes of ED, influential or risk factors for ED, vascular parameters, and serum biochemical markers. Fifty-two ED patients aged 20-40 years without known etiology and 22 age-matched normal subjects were enrolled. The further assessment of two groups focused on vascular endothelial function and glycometabolic state. Relationships among the IIEF-5 scores, flow-mediated dilation (FMD), and GSP were analyzed in cases vs. controls, using Pearson's correlation and multiple linear regression analysis. No significant differences in baseline characteristics, cardiovascular risks, and conventional biomarkers were found between testing and control groups, except fasting blood glucose level (4.69 ± 0.50 vs. 4.29 ± 0.48, P = 0.003). FMD values were significantly reduced in cases compared with controls and correlated positively with IIEF-5 scores (r = 0.629, P < 0.001). GSP levels were significantly increased in the ED cases compared with controls and correlated negatively with IIEF-5 scores (r = -0.504, P < 0.001) and FMD values (r = -0.469, P < 0.001). These parameters independently predicted ED presence. The positive predictive value of FMD > 11.55% for excluding ED and of GSP > 210.50 mg/L for diagnosing ED were 86.4% (area under the curve [AUC]: 0.942, specificity: 88.4%) and 84.5% (AUC: 0.864, specificity: 72.7%), respectively. Underlying glycometabolic disorder and subclinical endothelial dysfunction may be served as early markers for organic ED in young ED patients without well-known related risk factors. GSP level may improve our ability to predict endothelial dysfunction and erectile dysfunction.