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

Abstract

Abstract Background Hyperuricemia has been associated with high mortality rates in patients with acute myocardial infarction. The role and the prognostic relevance of increased serum uric acid (SUA) in patients with acute coronary syndrome (ACS) are still under debate Aim We sought to assess the association between elevated admission levels of SUA and in-hospital adverse outcomes in a real-world patient population with ACS and to investigate the potential incremental prognostic value of SUA added to GRACE score Methods 1088 consecutive patients admitted with a diagnosis of ACS to the Coronary Care Unit of two Hospitals were enrolled. Medical history, clinical characteristic, biochemical and electrocardiographic findings, angiographic data, treatments administered during hospitalization were all collected on an electronic database. All patients' data were entered prospectively in the database of the two hospitals and retrospectively analysed. Results The mean age was 68 years (IQR 60–78). Less than one-third of the total population was female (24%). Diabetes mellitus was present in 308 (28%) patients. The proportion of patients with STEMI and NSTEMI/UA was quite similar: 504 (46%) patients had a diagnosis of STEMI and 584 (54%) patients had a diagnosis of NSTEMI/UA. The GRACE score was 133 (IQR 112–156). In-hospital mortality rate was 2.3% in the overall population. Two variables were associated with a significantly increased risk of in-hospital death at the multivariate analysis: 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). To investigate the potential incremental prognostic value of SUA added to GRACE score for in-hospital death, we analyzed the results of adding hyperuricemia as categorical variable to the original GRACE risk model (GRACE-SUA score). 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; p<0.0001). The addition of hyperuricemia to the GRACE score led to reclassifying 18 of 211 (8.5%) patients without in-hospital deaths from high to low risk. No patients with o without events were incorrectly reclassified. The net-reclassification index (NRI) of the GRACE-SUA score was 1.7% (z value of 4.3; p<0.001). Conclusions High admission levels of SUA are positively and independently associated with in-hospital adverse outcomes and mortality in a contemporary and unselected population of ACS patients. The inclusion of SUA to GRACE risk score seems to lead to a more accurate prediction of in-hospital mortality and to improve risk classification in this study population. Funding Acknowledgement Type of funding source: None