Relationship between serum uric acid level and vascular injury markers in hemodialysis patients

Purpose It has been reported that hyperuricemia causes vascular endothelial injury. Most hemodialysis patients present with hyperuricemia and also with vascular injury, resulting in cardiovascular diseases (CVD). However, the association of serum uric acid (sUA) with vascular injury markers in hemodialysis patients remains unclear. This study aimed to investigate this and discuss the mechanism by which uric acid causes vascular injury. Methods We enrolled 48 Japanese maintenance hemodialysis patients without any history of CVD. The association between sUA level and three vascular injury markers (reactive hyperemia index [RHI], ankle-brachial index [ABI], and cardio ankle vascular index [CAVI]) was investigated by linear- and logistic regression analyses. Results The median natural logarithm RHI (LnRHI) was 0.36. Linear regression analysis revealed a significant positive correlation between sUA level and LnRHI (beta = 0.42,p = 0.001) in all patients. Moreover, a significant, strongly positive correlation was observed between sUA and LnRHI in patients who were treated with xanthine oxidase inhibitors (XOIs) (beta = 0.75,p = 0.001). Further, the linear analysis showed a significant negative correlation between sUA level and CAVI in patients who were treated with XOIs (beta = - 0.52,p = 0.049). sUA level was not significantly associated with ABI abnormality. Conclusions It is possible that a high level of sUA is significantly associated with better vascular endothelial function and condition of vascular tone in hemodialysis patients who were treated with XOIs. The findings suggest a significant paradox between sUA level and vascular endothelial function in hemodialysis patients; however, the opposite has been reported in patients without hemodialysis.