Prognostic value of serum uric acid: new-onset in and out-of-office hypertension and long-term mortality

Objective: Serum uric acid (SUA) has been associated with an increased cardiovascular risk, but no conclusive evidence exists on whether it is an independent risk factor or a reflection of other risk factors to which it is related. We examined the relationship of SUA with a number of cardiovascular variables [including risk factors never evaluated before, such as organ damage and out-of-office blood pressure (BP)], as well as its prognostic relevance in the population. Methods: In 2045 participants of the Pressioni Arteriose Monitorate E Loro Associazioni study, we measured, along with SUA, metabolic, renal, and anthropometric variables, left-ventricular mass index, and office, home and ambulatory BP. Cardiovascular and all-cause mortality was assessed over a 16-year follow-up period, and measurements were repeated 10 years after the initial data collection. Results: Baseline SUA had a near-normal distribution, with a mean value of 4.9±1.3 (SD) mg/dl and a significant direct relationship with BP and metabolic variables, serum creatinine and left-ventricular mass index. It was among the factors independently predicting new-onset home and ambulatory hypertension, the increased risk of developing these conditions for 1mg/dl increase of SUA after adjustment for all available potential confounders being 34 and 29%, respectively (P=0.015 and P=0.014). An increase in SUA of 1mg/dl also independently predicted cardiovascular and all-cause mortality, the fully adjusted increase in risk being 22% (P=0.03) and 12% (P=0.04), respectively. Conclusion: In the general population of the Pressioni Arteriose Monitorate E Loro Associazioni study, SUA correlated with a number of cardiovascular risk factors. Nevertheless, it independently predicts new-onset out-of-office hypertension, and long-term cardiovascular and all-cause mortality.