[Interleukin-18 combined with kidney injury molecule-1 predict 28-day mortality in patients with acute kidney injury treated with continuous renal replacement therapy in intensive care unit].

OBJECTIVE: To investigate the predict value of interleukin-18 (IL-18) combine with kidney injury molecule-1 (KIM-1) on 28-day mortality in patients with acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT) in intensive care unit (ICU), and to look for the start time of CRRT.

METHODS: A prospective observational study was conducted. The consecutive AKI critical patients who underwent CRRT from June 2017 to February 2018 admitted to ICU of the Fourth Hospital of Hebei Medical University were enrolled. Patients were divided into AKI 2 stage and AKI 3 stage groups according to the guidelines for Kidney Disease: Improving Global Outcomes (KDIGO). Basic vital signs were recorded for all enrolled patients, and ventilator parameters were recorded for patients on ventilation. Urine specimens were collected before CRRT, and IL-18 and KIM-1 levels were measured by enzyme-linked immunosorbent assay (ELISA). The patients were followed up for 28 days. The receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of urinary IL-18 and KIM-1 for prognosis.

RESULTS: During the study period, 38 patients were treated. The patients with ICU stayed for less than 3 days, chronic obstructive kidney disease, intra-abdominal hypertension (IAH), diuretics usage within 4 hours or renal replacement therapy before urine collection were excluded. Finally, 30 patients were enrolled, including 12 patients with AKI phase 2 and 18 patients with AKI phase 3. There was no significant difference in basic medical characteristics such as gender, age, height, weight, basic vital signs, basic renal function, or severity of disease between AKI 2 stage and AKI 3 stage groups. Compared with the AKI 2 stage group, the level of urine KIM-1 in the AKI 3 stage group was significantly increased [ng/L: 6 195.6 (5 892.6, 7 935.4) vs. 5 487.5 (4 769.8, 6 353.4), P < 0.01], but urine IL-18 level was not statistically significant [ng/L: 52.1 (48.1, 62.6) vs. 53.9 (52.0, 57.2), P > 0.05]. All patients were followed up for 28 days. The 28-day all-cause mortality rate of AKI 2 stage group was significantly lower than that of AKI 3 stage group [16.7% (2/12) vs. 66.7% (12/18), P < 0.05]. ROC curve analysis showed that urinary IL-18 had a small predictive value for the 28-day mortality of AKI patients undergoing CRRT, and KIM-1 had a certain predictive value, and the combined value of the combined detection was greater, and the area under ROC curve (AUC) was 0.786 [95% confidence interval (95%CI) = 0.598-0.914, P = 0.001] with a sensitivity of 50.0% and a specificity of 100%.

CONCLUSIONS: Urine IL-18 combined with urine KIM-1 has a high predictive value for the prognosis of patients with AKI. For critically ill patients with AKI, initiation of CRRT treatment in AKI 2 stage can significantly reduce the 28-day mortality as compared with that in AKI 3 stage.