Procalcitonin and N-Terminal Pro-B-Type Natriuretic Peptide for Prognosis in Septic Acute Kidney Injury Patients Receiving Renal Replacement Therapy

BACKGROUND: Sepsis is a complex clinical syndrome leading to severe sepsis and septic shock. It is very common in the intensive care unit with high mortality. Thus, judging its prognosis is extremely important. Procalcitonin (PCT) and -N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels are commonly elevated in sepsis patients, but only a few are discussed in the septic acute kidney injury patients (AKI) who received renal replacement therapy (RRT). Our study is aimed at investigating the prognostic value of PCT and NT-proBNP in septic AKI patients who received RRT. METHODS: This was a retrospective study of septic AKI patients who underwent RRT in a Chinese university hospital. All enrolled patients tested PCT and NT-proBNP at RRT initiation. PCT and NT-proBNP levels were compared between the survivors and non-survivors. Receiver operating characteristic (ROC) curves of the 2 biomarkers were performed for predicting in-hospital mortality. According to the median value of PCT (16.2 ng/mL) and NT-proBNP (10,271 pg/mL), patients were divided into 4 groups (low PCT and low NT-proBNP; high PCT and low NT-proBNP; low PCT and high NT-proBNP; high PCT and high NT-proBNP). The Kaplan-Meier survival curves were used to analyze the 28-day survival rate in the 4 groups. RESULTS: A total of 81 patients were enrolled in the study. Of which, 48 (59.3%) patients died during hospitalization. The median of NT-proBNP in non-survivors was significantly higher than in survivors (p = 0.001), while PCT had no significant difference (p = 0.412). The area under the ROC curve of PCT and NT-proBNP for predicting in-hospital mortality was 0.561 (95% CI 0.426-0.695) and 0.729 (95% CI 0.604-0.854). Kaplan-Meier survival curve analysis showed that increased NT-proBNP level was associated with 28-day mortality while combined with PCT there was no statistical difference in 4 different level groups. CONCLUSION: NT-proBNP has a certain predictive value for the prognosis in septic AKI patients who received RRT. It seems that the initial PCT value for prognosis is limited. The combination of PCT and -NT-proBNP to evaluate the prognosis in these critically ill patients is currently unclear.