Interrelations Between Serum Uric Acid, Silent Myocardial Infarction, and Mortality in the General Population

Whether elevated uric acid (UA) is associated with silent myocardial infarction (SMI) or whether their joint association predicts an increased risk of mortality has not been explored. This analysis included 6,323 participants (58.4 ± 13.1 years, 53.9% women, and 49.7% Non-Hispanic whites) without clinical cardiovascular disease (CVD) from third National Health and Nutrition Examination Survey. SMI was defined as electrocardiographic evidence of myocardial infarction (MI) without a history of MI. Multivariable logistic regression model was used to examine the cross-sectional association between baseline UA and SMI. Cox-proportional hazard analysis was used to calculate hazard ratio (HR) with 95% confidence interval (CI) for the risk of all-cause and CVD mortality with UA in the absence and presence of SMI. The higher baseline level of UA was associated with higher odds of baseline SMI. The prevalence of SMI was 0.79%, 1.18%, 1.59%, and 2.27% across the UA quartiles respectively; multivariable-adjusted odds ratio (95% CI): 2.37 (1.11 to 5.08) comparing the upper with lower quartile. During a median follow up of 14 years, there were 1916 all-cause death of whom 774 were CVD deaths. Compared with participants with the lowest UA quartile values and without SMI, those with highest UA had a 29% increased the risk of all-cause mortality (multivariable-adjusted HR: [95% CI]: 1.29 [1.10 to 1.51]). This risk increased by 107% in the presence of SMI (multivariable-adjusted HR (95% CI): 2.07 (1.38 to 3.10)). Similar results were observed for CVD mortality. SMI carried an increased risk of all-cause and CVD mortality only in higher quartiles of UA. In conclusion, the strong association of UA with SMI and the additive effect of UA and SMI on mortality further support the potential role of UA as a marker of poor outcomes.