Uric acid is an independent predictor of arterial stiffness in hypertensive patients

Abstract

Increased arterial stiffness is an important marker for target organ damage in essential hypertension. Both serum uric acid (UA) and C-reactive protein (CRP) were reported to be associated with target organ damage. However, the influences of UA and CRP on large arterial stiffness were not well elucidated. This study included 200 essential hypertension patients (64 women) whose age was between 20 and 50 years old (mean age 41 +/- 8 years). None of the patients had diabetes mellitus or overt end-organ damage. Arterial stiffness was assessed by pulse-wave velocity (PWV) measured by tonometry from carotid to radial artery. Serum UA, high-sensitivity CRP (hsCRP), glucose, insulin, and lipid profiles were measured at the same time in each patient. PWV levels were significantly correlated with mean blood pressure (r = 0.245, P < 0.001), diastolic blood pressure (r = 0.323, P < 0.001), high-density lipoprotein (r = -0.169, P = 0.016), and UA (r = 0.234, P = 0.001), but not age, body mass index, blood sugar, insulin, low-density lipoprotein, triglyceride, and hsCRP. Pulse-wave velocity levels were significantly higher in males (8.9 +/- 1.2 vs 8.2 +/- 1.2 m/s, P < 0.001) and smokers (9.3 +/- 1.1 vs 8.5 +/- 1.2 m/s, P < 0.001). Uric acid was significantly correlated with hsCRP (r = 0.294, P < 0.001). After multivariate analysis controlling for all possible confounding factors, UA (odds ratio 1.28, 95% confidence interval 1.02-1.61, P = 0.032) was still independently associated with increased PWV. In conclusion, UA but not hsCRP was independently associated with increased PWV in essential hypertension. Although UA was correlated with hsCRP, the association between UA and PWV was not through the effect of enhanced inflammation.