Objective: To evaluate the early diagnosis value of blood neutrophil gelatinase-associated lipocalin (NGAL) and interleukin-18 (IL-18) in patients with sepsis-induced acute kidney injury (AKI).
Methods: A prospective case controlled study was conducted. Fifty-six patients with sepsis but without renal disease admitted to intensive care unit (ICU) of Shanxi People's Hospital from April 2014 to April 2015 were enrolled. Blood lactic acid and acute physiology and chronic health evaluation II (APACHE II) score at ICU admission were recorded. The urine output, blood urea nitrogen (BUN), serum creatinine (SCr), NGAL, IL-18 and tumor necrosis factor-α (TNF-α) were continuously monitored for 48 hours. The patients were divided into AKI group and non-AKI group according to the diagnostic criteria of Kidney Disease: Improving Global Outcomes (KDIGO). The changes trend in above parameters between the two groups at different time points were compared. The early diagnostic value of NGAL, IL-18, and SCr for sepsis-induced AKI was evaluated by receiver operating characteristic curve (ROC).
Results: Compared with non-AKI group, with the time prolongation after ICU admission, the traditional parameters reflecting AKI urine output in sepsis-induced AKI group was decreased gradually, BUN and SCr were gradually increased, and a statistically significant difference was found at 12 hours between the two groups [BUN (mmol/L): 11.8±3.5 vs. 8.2±3.5, SCr (μmol/L): 88.6±11.3 vs. 74.0±11.0, both P < 0.01]; but the new indicators NGAL and IL-18 reflecting AKI had a statistically significant difference at 6 hours [NGAL (μg/L): 426.7±90.7 vs. 382.3±67.9, IL-18 (ng/L): 75.7±9.3 vs. 70.9±7.3, both P < 0.05]. It was shown that in AKI group, NGAL and IL-18 compared with BUN and SCr increased at least 6 hours ahead of schedule. The area under ROC curve (AUC) of 6-hour NGAL and IL-18 in patients with sepsis-induced AKI were 0.821 [95% confidence interval (95%CI) = 0.713-0.931] and 0.719 (95%CI = 0.584-0.853) respectively, superior to SCr (AUC = 0.677, 95%CI = 0.528-0.825). The cutoff value of NGAL was 363.58 μg/L, and the sensitivity and specificity were 88.0% and 86.7% respectively.
Conclusions: NGAL and IL-18 in the early prediction of sepsis patients with AKI are better than SCr, and NGAL was most sensitive. Therefore, NGAL can be used as an early biomarker for the diagnosis of AKI in patients with sepsis.