Background: Continuous renal replacement therapy (CCRT) is a frequently used modality for the support of intensive care patients with acute kidney injury (AKI). Nevertheless, there are no objective criteria for the discontinuation of CRRT. The purpose of this study was to investigate whether urine neutrophil gelatinase-associated lipocalin (uNGAL) alone or in combination with urine output could be used as a diagnostic test for renal function recovery in ICU patients on CRRT. Methods: This was a single-centre prospective observational study including patients with acute kidney failure needing CRRT. Sixty-nine patients were enrolled, and 54 completed the study. Of the 54 patients, 22 recovered renal function (REC), defined as dialysis independency at 72 h from discontinuation, while 32 patients did not (NREC). Urine NGAL was measured at 0, 6, 12, and 24 h after CRRT discontinuation. The cumulated urine output was measured for 24 h prior to discontinuation and at 6, 12, and 24 h after discontinuation. Missing uNGAL values were calculated by interpolation. The Youden's index was used to calculate cutoff values in order to define uNGAL and urine output single variable and 2-variable diagnostic tests with the optimum prediction of successful CRRT discontinuation. Results: Baseline characteristics at CRRT initiation were similar between groups. Compared to the NREC group, the REC group had significantly higher urine output (p < 0.0001) and lower uNGAL (p < 0.001) at all time points, except for uNGAL at 24 h (p < 0.24). The best uNGAL predictor for successful CRRT discontinuation was uNGAL at 6 h after discontinuation (predictive value 80%). The best single predictor was cumulated urine output 24 h before discontinuation (predictive value 85%). The combinations of uNGAL at 6 h (cut-off 1650 μg/L) with cumulated urine output 24 h prior to discontinuation (cut-off 210 ml) proved to be the superior tests (using either "or" or "and"), with predictive values of 93% (successful CRRT discontinuation) and 92% (dialysis dependency). Conclusions: With a predictive value of 93%, the combination of uNGAL at 6 h after and the cumulated urine output 24 h prior to CRRT cessation proved to be the best diagnostic test for successful CRRT discontinuation in ICU patients.

Background: Continuous renal replacement therapy (CCRT) is a frequently used modality for the support of intensive care patients with acute kidney injury (AKI). Nevertheless, there are no objective criteria for the discontinuation of CRRT. The purpose of this study was to investigate whether urine neutrophil gelatinase-associated lipocalin (uNGAL) alone or in combination with urine output could be used as a diagnostic test for renal function recovery in ICU patients on CRRT.Methods: This was a single-centre prospective observational study including patients with acute kidney failure needing CRRT. Sixty-nine patients were enrolled, and 54 completed the study. Of the 54 patients, 22 recovered renal function (REC), defined as dialysis independency at 72 hours from discontinuation, while 32 patients did not (NREC). Urine NGAL was measured at 0, 6, 12, and 24 hours after CRRT discontinuation. The cumulated urine output was measured for 24 hours prior to discontinuation and at 6, 12, and 24 hours after discontinuation. Missing uNGAL values were calculated by interpolation. The Youden’s index was used to calculate cut-off values in order to define uNGAL and urine output single variable and 2-variable diagnostic tests with the optimum prediction of successful CRRT discontinuation. Results: Baseline characteristics at CRRT initiation were similar between groups. Compared to the NREC group, the REC group had significantly higher urine output (p<0.0001) and lower uNGAL (p<0.001) at all time points, except for uNGAL at 24 hours (p<0.24). The best uNGAL predictor for successful CRRT discontinuation was uNGAL at 6 hours after discontinuation (predictive value 80%). The best single predictor was cumulated urine output 24 hours before discontinuation (predictive value 85%). The combinations of uNGAL at 6 hours (cut-off 1650 µg/L) with cumulated urine output 24 hours prior to discontinuation (cut-off 210 ml) proved to be the superior tests (using either “or” or “and”), with predictive values of 93% (successful CRRT discontinuation) and 92% (dialysis dependency).Conclusions: With a predictive value of 93%, the combination of uNGAL at 6 hours after and the cumulated urine output 24 hours prior to CRRT cessation proved to be the best diagnostic test for successful CRRT discontinuation in ICU patients.Clinical trial registration: N/A

Background: Continuous renal replacement therapy (CCRT) is a frequently used modality for the support of intensive care patients with acute kidney failure (AKI). Nevertheless, there are no objective criteria for the discontinuation of CRRT. The purpose of this study was to investigate whether urine neutrophil gelatinase-associated lipocalin (uNGAL) alone or in combination with urine output could be used as a diagnostic test for renal function recovery in ICU patients on CRRT.Methods: This was a single-centre prospective observational study including patients with acute kidney failure needing CRRT. Sixty-nine patients were enrolled, and 54 completed the study. Of the 54 patients, 22 recovered renal function (REC), defined as dialysis independency at 72 hours from discontinuation, while 32 patients did not (NREC). Urine NGAL was measured at 0, 6, 12, and 24 hours after CRRT discontinuation. The cumulated urine output was measured for 24 hours prior to discontinuation and at 6, 12, and 24 hours after discontinuation. Logistic regression was used to calculate the missing 6-hour uNGAL values by interpolation. The Youden index was used to calculate cut-off values. A P-value <0.05 was considered statistically significant.Results: Baseline characteristics at CRRT initiation were similar between groups. Compared to the NREC group, REC patients had significantly higher urine output (p<0.0001) and lower uNGAL (p<0.001) at all time points, except for uNGAL at 24 hours (p<0.24). The best single predictor for renal recovery was the cumulated urine output 24 hours after discontinuation (predictive value 83%). Combining uNGAL at 6 hours (cut-off 1650 µg/L) with the cumulated urine output during the 24 hours prior to discontinuation (cut-off 210 ml) proved superior, with predictive values of 92% (CRRT dependency) and 93% (renal function recovery).Conclusions: With predictive values up to 93%, the combination of uNGAL at 6 hours and the cumulatated urine output during the 24 hours prior to CRRT cessation proved to be the best diagnostic test for renal function recovery in ICU patients.Clinical trial registration: N/A