Plasma uric acid response to rasburicase: early marker for acute kidney injury in tumor lysis syndrome?

Acute kidney injury (AKI) is associated with high morbidity and mortality in tumor lysis syndrome (TLS). The goal of this study was to assess a practical approach involving a simple risk-prediction model for AKI in patients at high risk for clinical TLS treated according to standardized guidelines. We collected data on 62 patients at high risk for clinical TLS. We evaluated whether the magnitude of the plasma uric acid decrease in response to rasburicase predicted AKI. According to RIFLE criteria (Risk, Injury, Failure, sustained Loss, End-stage kidney disease), 41 (66.1%) patients had AKI. AKI was associated with higher hospital (26.8% vs. 0%, p = 0.01) and 6-month (41.4% vs. 9.5%, p = 0.04) mortality. The plasma uric acid decrease after rasburicase was significantly larger in patients who did not develop AKI than in those who did (95% vs. 84%; p < 0.01). By multivariate analysis, independent determinants of AKI were hypertension and a plasma uric acid decrease smaller than 92.9% 6 h after rasburicase.