Serum uric acid levels correlate with the severity and the mortality of primary pulmonary hypertension

Serum uric acid (UA), the final product of purine degradation, has been pro posed to be a marker for impaired oxidative metabolism and a possible predi ctor of mortality in patients with chronic heart failure. To elucidate whet her serum UA correlates with the severity and the mortality of primary pulm onary hypertension (PPH), serum UA was assessed in 90 patients with PPH tog ether with other clinical variables. Right heart catheterization was perfor med in all patients. Serum UA was significantly elevated in patients with P PH compared with age-matched control subjects (7.5 +/- 2.5 versus 4.9 +/- 1 .2 mg/ml, p < 0.001). Serum UA negatively correlated with cardiac output (r = -0.52, p < 0.001) and positively correlated with total pulmonary resista nce (r = 0.57, p < 0.001). Serum UA significantly decreased from 7.1 +/- 1. 9 to 5.9 +/- 1.6 mg/dl with vasodilator therapy, associated with a reductio n in total pulmonary resistance from 22 +/- 6 to 17 +/- 7 Wood units. Durin g a mean follow-up period of 31 mo, 53 patients died of cardiopulmonary cau ses. Among noninvasive variables, serum UA was independently related to mor tality by a multivariate Cox proportional-hazards analysis. The Kaplan-Meie r survival curves according to the median value of serum UA demonstrated th at patients with high serum UA had a significantly higher mortality rate th an did those with low serum UA (log-rank test, p < 0.01). These results sug gest that serum UA increases in proportion to the clinical severity of PPH and has independent association with long-term mortality of patients with P PH.