Background: It is unknown whether the dose of enoxaparin can be optimised, without increasing the risk of bleeding, in critically ill patients with acute kidney injury (AKI). Neutrophil gelatinase-associated lipocalin (NGAL) is associated with AKI, and the subsequent need for continuous renal replacement therapy (CRRT). The predictive value of plasma and urine NGAL for renal recovery is not established.

Methods: A double-blinded randomized trial was conducted in medico-surgical intensive care units across Denmark to establish markers of renal recovery, and to determine whether a dose of 1 mg/kg enoxaparin once daily (QD) would improve thromboprophylaxis. Patients were randomly assigned to receive 1 mg/kg enoxaparin QD or 40 mg enoxaparin QD upon commencement of CRRT. The primary outcome was the occurrence of venous thromboembolism (VTE). Secondary outcomes included major bleeding, NGAL levels and urine output.

Results: Poor accrual led to early study closure after enrolment of only 19 patients. Patients were comparable with respects to baseline demographics, the interval prior to start of dialysis, and the duration of dialysis. No episodes of VTE or of major bleeding occurred. During the dialysis -free interval, plasma NGAL levels were higher in non-renal recovery (1074 [± 694] ng/mL) compared to renal recovery patients (296[± 197] ng/mL; P = 0.01), and urine NGAL levels were higher in non-renal recovery (3885 [± 2722] ng/mL) compared to renal recovery patients (597 [± 565] ng/mL; P = 0.006). Multiple regression analysis showed that only urine NGAL could independently predict recovery from AKI (P =0.006).

Conclusion: Our study did not recruit enough patients to test the hypothesis that 1 mg/kg enoxaparin QD could safely improve thromboprophylaxis. However the study suggests that urine NGAL may be able to predict renal recovery in critically ill patients, and allow proper utilization of resources. (EU Clinical Trials Register EudraCT Number: 2012-004368-23; URL: https://www.clinicaltrialsregister.eu/ctr-search/trial/2012-004368-23/DK).