Serum uric acid is associated with mortality and heart failure hospitalizations in patients with complicated myocardial infarction: findings from the High-Risk Myocardial Infarction Database Initiative.

Abstract

Serum uric acid (SUA) levels are associated with poorer outcomes in healthy cohorts and patients with stable and unstable coronary heart disease. We investigated the relationship between SUA and clinical outcomes in subjects with acute myocardial infarction (MI) complicated by reduced left ventricular (LV) function, heart failure (HF), or both. Univariable and multivariable Cox proportional hazards modelling was performed to study the association of baseline SUA and all-cause mortality, cardiovascular (CV) mortality, and HF hospitalization in an individual patient meta-analysis of four merged large randomized trials (CAPRICORN, EPHESUS, OPTIMAAL, and VALIANT). Three trials (excluding VALIANT) reported SUA, which was available in a total of 12 677 subjects. The ranges of SUA for quartiles I-IV were 45-280, 281-344, 345-420, and 420-1640 mmol/L, respectively. While almost 90% of patients in the lowest SUA quartile were alive after a mean follow-up of 23 ± 11 months, <70% were alive in the highest SUA quartile. Compared with the lowest SUA quartile as reference, hazard ratios (HRs) and 95% confidence intervals (CIs) of SUA quartiles III and IV showed an increase in all-cause mortality [HR 1.18, 95% CI 0.95-1.46, and HR 1.36, 95% CI 1.11-1.67) and CV mortality (HR 1.27, 95% 1.01-1.61, and HR 1.47, 95% CI 1.17-1.83). SUA quartiles III and IV also exhibited increased HF hospitalization (HR 1.22, 95% CI 1.09-1.36, and HR 1.28, 95% CI 1.14-1.43; P < 0.001 for all comparisons) in multivariable analyses. The addition of SUA was associated with a significant improvement in reclassification to predict CV mortality (net reclassification improvement 17.6%, 95% CI 14.9-20.5%, P < 0.001). Elevated SUA is associated with poor outcomes in patients after MI complicated by reduced LV function, HF, or both. The quantification of SUA, a low-cost routinely available biomarker, could improve risk stratification of patients with complicated MI.