Adding Hyperuricemia to Traditional Cardiac Risk Factors Does Not Improve Ability to Predict Cardiac or Total Death in the Asymptomatic Taiwanese General Population

Background: Although hyperuricemia is associated with cardiovascular disease, such as coronary heart disease (CHD), stroke and hypertension, whether or not including it among traditional risk factors improves the ability to better predict cardiac mortality and total cause of death rates remains controversial. Methods and Results: This was an observational study based on 57,100 participants without overt cardiovascular disease who were enrolled during routine health examinations at Taipei Veterans General Hospital. The participants' mean age was 52.3 +/- 13.4 years. Researchers estimated their serum concentrations of uric acid, and the study used future cardiac and all-cause death as the primary endpoints. During an average follow-up period of 5.4 +/- 3.0 years, there were 1,889 deaths, including 231 cardiac deaths among the study subjects. In a multivariable-adjusted analysis with traditional cardiovascular risk factors, the hazard ratio of cardiac death associated with hypeniricemia was 1.63 (95% confidence interval [CI]: 1.19-2.22) and 1.60 (95% CI: 0.95-2.71) respectively, for males and females. The hazard ratio for death from all causes associated with hypeniricemia was 1.12 (95% CI: 1.00-1.26) and 1.41 (95% Cl: 1.17-1.70) for males and females, respectively. The addition of hyperuricemia to the roster of traditional risk factors for cardiac death increased the C statistic from 0.79 (95% CI, 0.76-0.82) to 0.80 (95% Cl, 0.77-0.83) for males, and increased it from 0.89 (95% Cl, 0.85-0.92) to 0.89 (95% Cl, 0.85-0.92) for females; however, neither had statistical significance. Furthermore, adding hyperuricemia to known risk factors produced an integrated discrimination improvement of 0.009 and -0.0003 respectively, for males and females, with a 4.11% improvement according to net reclassification analysis (p = 0.102), and 0.13% improvement according to net reclassification improvement (p = 0.484). Conclusion: Our results suggest that hyperuricemia is an independent risk factor for predicting cardiac or all-cause death, although it had borderline significance for females in cardiac death models. However, adding hyperuricemia to traditional cardiac risk prediction models did not significantly improve the ability of the model to predict the risk of cardiac or all-cause death, regardless of whether we used ROC analysis or reclassification methods. Therefore, hyperuricemia per se should not be designated as a treatment target for reducing cardiac or even all-cause death in the general Taiwanese population.