Relationship Between Serum UA And Endothelial Function In Hypertensive Patients With Metabolic Syndrome

Objective:To investigate the association between Serum Uric Acid andendothelial function in Chinese hypertentive patients with or withoutMetabolic Syndrome (MS).Methods:A total of616mild hypertensive outpatients (331men,284women; aged59.97±12.02yr) were enrolled and87age-and gender-matched healthynormotensive subjects (46men,41women; aged59.21±10.98yr) wereselected as control in The First Affiliated Hospital of Fujian MedicalUniversity between August2008and April2013. The patients were dividedinto two groups according to the presence or absence of MS: hypertensivepatients with MS (MS group, n=239) and without MS (NMS group, n=376).high-resolution vascular ultrasound was used to assess the endothelialfunction. Reactive hyperemia of the brachial artery was used to detectendothelium-dependent dilatation (FMD/EDD); endothelium-independentvasodilation (EID) was determined after sublingual administration ofnitroglycerin. SUA was measured by the uricase peroxidase method.Results:Serum uric acid concentrations and the prevalence of hyperuricemiaincreased gradually among controls, NMS group and MS group[323.77±104.49vs353.63±92.83vs390.90±101.42umol/l, p<0.01;4/87(4.6%) vs120/376(31.9%) vs120/239(50.2%), p<0.01], but values of EDDshowed the inverse trend (12.03±4.51%vs8.98±4.32%vs8.23±4.58%, p<0.01). There was no difference of endothelium-independent dilatationbetween MS group and NMS group，but lower than NC group (15.87±6.67%vs16.64±7.49%vs18.42±7.75, p<0.05). In hypertensive with MS, EDD weresignificantly lower in those with hyperuricemia than that in those withouthyperuricemia (7.48±4.27%vs8.91±4.77%, P<0.05); Correlations betweenserum UA levels with EDD were significance (r=-0.185, p <0.01). Aftergender stratification, we found that patients with hyperuricemia hadlower values of EDD compared with those without hyperuricemia (7.20±4.54%vs9.31±4.98%, P<0.05) in men with MS group; SUA were correlatedwith EDD(r=-0.248,p <0.01). After futher stratification of age, EDD ofpatiens with hyperuricemia was significantly less than those withouthyperuricemia (7.12±4.49%vs9.98±5.78%, P<0.05) in men aged less than60years; SUA levels were also correlated with EDD (r=-0.314, p<0.01).Finally,logistic regression analysis showed that a50umol/L increase inthe serum concentration of SUA signaled a23.1%higher risk forendothelial dysfunction in men with MS group, and for in men aged lessthan60years with MS group, the risk could increase45.0%.Conclusions:Hypertensive patients with MS have worse endothelium-dependentdilatation and higher levels of Serum uric acid. In men aged less than60years old, SUA levels are inversely associated with endothelialfunction.