Impact of admission serum acid uric levels on in-hospital outcomes in patients with acute coronary syndrome

Background: To assess the association between admission serum uric acid (SUA) levels and in-hospital outcomes in a real-world patients population with acute coronary syndrome (ACS) and to investigate the potential incremental prognostic value of SUA added to GRACE score (GRACE-SUA score). Methods: The data of consecutive ACS patients admitted to Coronary Care Unit of San Paolo and Niguarda hospitals in Milan (Italy) were retrospectively analyzed. Results: 1088 patients (24% female) were enrolled. Mean age was 68 years (IQR 60–78). STEMI and NSTE-ACS patients were 504 (46%) and 584 (54%) respectively. SUA (OR 1.72 95%CI 1.33–2.22, p < 0.0001) and GRACE score (OR 1.04 95%CI 1.02–1.06, p < 0.0001) were significantly associated with an increased risk of in-hospital death at the multivariate analysis. Admission values of SUA were stratified in four quartiles. Rates of acute kidney injury, implantation of intra-aortic balloon pump and non-invasive ventilation use were significantly higher in the last quartile compared to Q1, Q2 and Q3 (p < 0.01). The areas under the ROC curve (AUC) for GRACE score and for SUA were 0.91 (95% CI 0.89–0.93, p < 0.0001) and 0.79 (95% CI 0.76–0.81, p < 0.0001) respectively. The AUC was larger for predicting in-hospital mortality with the GRACE-SUA score (0.94; 95% CI 0.93–0.95). Conclusions: High admission levels of SUA are independently associated with in-hospital adverse outcomes and mortality in a contemporary population of ACS patients. The inclusion of SUA to GRACE risk score seems to lead to a more accurate prediction of in-hospital mortality in this study population.