Uric Acid: a Cardiovascular Risk Factor in Patients with Recent Myocardial Infarction

Background: To date uric acid (UA) is not considered a cardiovascular risk factor, although evidence about a relationship between UA and cardiovascular diseases has been reported.

Methods: Information from 10,840 patients enrolled in the GISSI-Prevenzione trial was used to evaluate the relationship between UA and risk for total mortality and cardiovascular events (CVE). UA levels were categorized in quintiles, as ≤ 4.5 (Q1), 4.6 to 5.3 (Q2), 5.4 to 6.0 (Q3), 6.1 to 6.8 (Q4) and >6.8 (Q5) mg/dL. Multivariable analysis was used to estimate the relative risks (HR) of outcome measures across categories of UA. The analysis of the area under the receiver operating characteristic curve (AUC), the net reclassification improvement (NRI), and the integrated discrimination improvement (IDI) tests were used to evaluate the incremental prognostic information of UA.

Results: During 36,802 person-years of follow-up, 974 deaths and 1120 cardiovascular events occurred. We found a statistically significant association between high UA and total mortality [HR, P value]: Q1 [reference category, 1.00]; Q2 [1.13, 0.267]; Q3 [1.06, 0.619]; Q4 [1.23, 0.063]; Q5 [1.63, <0.0001], test for trend P<0.0001. Similar results were obtained for cardiovascular events [HR, P value]: Q1 [reference category, 1.00]; Q2 [1.12, 0.271]; Q3 [1.19, 0.094]; Q4 [1.25, 0.031]; Q5 [1.38, 0.002], test for trend P=0.0009. The prognostic accuracy of prediction models for CVE was significantly increased by adding UA to classical cardiovascular risk factors (AUC P=0.0041; NRI P=0.0004; IDI P<0.0001).

Conclusion: High UA may be considered a risk factor for death and CVE.