Kinetic changes in serum procalcitonin predict persistent acute kidney injury in critical patients

PURPOSE Persistent acute kidney injury (AKI) has been shown to be closely associated with poor prognosis in critical patients. Recent studies have shown that procalcitonin (PCT) is valuable for the early prediction of AKI in critically patients. Our aim was to determine whether PCT and its kinetic changes could predict the occurrence of persistent AKI in critical patients. METHODS This is a prospective observational study. The definition of AKI was based on the Kidney Disease: Improving Global Outcomes criteria. Persistent AKI was defined as renal function that does not return to baseline serum creatinine levels within 48 h. Blood samples were obtained at the onset of AKI and two subsequent days of hospital stay. 24-h PCT change (ΔPCT-24 h) was defined as 24 h PCT minus baseline PCT (day 0). RESULTS A total of 91 critical patients with AKI were included in this study. The persistent AKI group had a stepwise increase in PCT concentration. ΔPCT-24 h was higher in the persistent AKI group (p < .01). Logistic regression analysis showed that ΔPCT-24 h (p = .04) was independent predictors of persistent AKI. The receiver operating characteristic curves showed that area under the curve of ΔPCT-24 h was 0.84 (p < .01), and the cut-off value for PCT to predict persistent AKI was 0.56 ng/ml. CONCLUSION Our study showed that the observation of kinetic changes in PCT is more significant for the early prediction of persistent AKI than the index of PCT at a single time point. ΔPCT-24 h is a good predictor of persistent AKI in critical patients.