Hyperuricemia as an Outcome Predictor in Patients with ST-Segment Elevation Myocardial Infarction: Too Good to be True?

Hyperuriacemia has been reported as an independent predictor of shortand long-term prognosis in patients with acute coronary syndrome. 1,2 In the recent issue of Acta Cardiologica Sinica, Akgul et al. advocated that uric acid > 5.7 mg/dl was associated with increased in-hospital and six-month cardiovascular death in Turkish patients with ST-segment elevation myocardial infarction (STEMI) undergoing angioplasty. 3 The level of uric acid upon hospital admission is a powerful predictor of six-month mortality, with a hazard ratio as high as 5.57. However, one aspect of the study must be noted. Although the enrollment of consecutive patients was stated, most patients in the study were at Killip’s class I (91.9%), which is not a common condition of general practice. In our own five-year retrospective cohort, we analyzed 944 STEMI patients undergoing primary percutaneous coronary intervention (pPCI). Patients with hyperuircemia (uric acid > 7 mg/dl) had elevated sixmonth (8.2% vs. 4.2%, p = 0.019) and one-year mortality (9.6% vs. 5.0%, p = 0.014). In univariate analysis, hyperuricemia was associated with higher one-year mortality (hazard ratio: 1.97, 95% CI: 1.18-3.27, Table 1). However, after adjustment for age, gender, body mass index, and creatinine, hyperuricemia was no longer a significant risk factor. In the subgroup analysis divided by Killip’s classification, hyperuricemia remained an independent predictor of one-year mortality in patients at Killip I, even after adjustment for potential confounders. However, the association is not significant in patients at Killip II to IV. There was a significant interaction between hyperuricemia and Killip’s classification associated with one-year mortality (p for interaction = 0.04). The same association was found between hyperuricemia and sixmonth mortality. We suggest that the association between hyperuricemia and the outcome of STEMI patients is dependent upon disease-severity and has the greatest impact on low risk groups (i.e., patients classified as Killip I). In general cases, when the disease severity of STEMI is divergent, the role of hyperuricemia on mortality is not so significant.