The value of serum uric acid as a mortality prediction in critically ill children

Objective: The role of initial serum uric acid on admission in critically ill patients is controversial; we presumed that uric acid level can predict the mortality of the admitted patients to intensive care unit as a simple test. Methods: Totally, 220 consecutively admitted children (96 girls, 124 boys) with mean age 3.5 years, who were at least 24 hours in pediatric intensive care unit (PICU), were enrolled in a prospective cohort study during January 2006 to December 2007. The subsequent PICU admission in the same hospitalization, those who were discharged from the hospital and then re-admitted to the PICU during the observation period, and the patients with chronic renal failure were excluded. Serum uric acid level was measured during the first day of PICU admission. Death or transfer from PICU was considered as final outcome. The statistical analysis was done by using linear regression analysis, ROC curve, Student t-test, and Chisquare. P value less than 0.05 was considered significant. Findings: From 44 patients who had serum uric acid level more than 8 mg/dl, 17 cases died showing with a higher relative risk of 1.88, higher mortality (P<0.05). The relative risk of death in patients who had serum uric acid >8 mg/dl and needed vasopressor was 1.04, and in those under mechanical ventilation 1.33. In patients who scored pediatric risk of mortality of >38 it was 1.4, and in septic cases 4 (P<0.05). Stepwise linear regression analysis showed that mainly the need for mechanical ventilation (P=0.001) and vasopressor had statistically significant correlation with the poor outcome (P=0.001). Conclusion: Uric acid level during the first day of intensive critical care admission is not an independent risk of mortality in PICU. Need for mechanical ventilation or inotropic agents was associated with poor outcome and only higher uric acid level in sepsis played an additive risk factor role.