Neutrophil gelatinase-associated lipocalin for predicting acute kidney injury in orthotopic liver transplantation: a systematic review and meta-analysis

Acute kidney injury (AKI) is associated with poor prognosis. New biomarkers, like neutrophil gelatinase-associated lipocalin (NGAL), are helpful for early warning of AKI. This study aims to investigate the accuracy of NGAL in evaluating the perioperative AKI of liver transplantation. The four databases, PubMed, Web of Science, Embase, and Cochrane Library, were searched for relevant studies published from database inception to August 2023. Results were pooled using random-effects models, and heterogeneity was examined. A total of 16 case-control studies with 1271 patients were included. The results showed that both preoperative [standardized mean difference (SMD) = 0.53; 95% confidence interval (CI): 0.15, 0.91; P < 0.001] and postoperative NGAL levels (SMD = 0.63; 95% CI: 0.24, 1.03; P < 0.001) were higher in the AKI group compared with the non-AKI group. Subgroup analysis by continents showed higher preoperative NGAL levels in AKI patients in the European population (SMD = 1.63; 95% CI: 0.55, 0.27; P = 0.003), but no differences in Asian, African, North American, and South American. Subgroup analysis by continents revealed higher postoperative NGAL levels in the European (SMD = 1.63; 95% CI: 0.55, 0.27; P = 0.002) and Asian populations (SMD = 0.42; 95% CI: 0.04, 0.81; P = 0.039). Higher postoperative NGAL levels in plasma and urine were observed in AKI patients compared with non-AKI patients [plasma (SMD = 1.29; 95% CI: 0.21, 2.38; P = 0.011), urine (SMD = 0.88; 95% CI: 0.18, 1.59; P = 0.035)], while there was no difference in African, North American, South American, and serum NGAL. NGAL level may be an important biomarker for early detection of AKI in the perioperative period of liver transplantation.