Neutrophil-to-lymphocyte ratio predicts acute kidney injury occurrence after gastrointestinal and hepatobiliary surgery

BACKGROUND: Postoperative acute kidney injury (AKI) is a complex pathological process involved intrarenal and systemic inflammation caused by renal hypoperfusion, nephrotoxic drugs and urinary obstruction. Neutrophil-to-lymphocyte ratio (NLR) is a marker of inflammation reflecting the progress of many diseases. However, whether NLR at admission can predict the occurrence of AKI after surgery in the intensive care unit (ICU) remains unknown. AIM: To clarify the relationship between NLR and the occurrence of AKI in patients with gastrointestinal and hepatobiliary surgery in the ICU. METHODS: A retrospective analysis of 282 patients receiving surgical ICU care after gastrointestinal and hepatobiliary surgery in our hospital from December 2014 to December 2018 was performed. RESULTS: Postoperative AKI occurred in 84 patients (29.79%) in this cohort. NLR by the multivariate analysis was an independent risk factor for occurrence of postoperative AKI in patients with gastrointestinal and hepatobiliary surgery in the ICU. In this cohort, receiver operating characteristic curves of AKI occurrence showed that the optimal cut-off value of NLR was 8.380. NLR was found to be significantly correlated with the white blood cell count, neutrophil count, lymphocyte count, arterial lactate and dialysis (P < 0.05). Additionally, NLR value at admission was higher in AKI patients compared with the non-AKI patients and increased with the severity of AKI. Patients with NLR ≥ 8.380 exhibited significantly higher incidences of postoperative AKI and severe AKI than patients with NLR < 8.380 (AKI: 38.12% vs 14.85%, P < 0.001; severe AKI: 14.36% vs 1.98%, P = 0.001). CONCLUSION: NLR at admission is a predictor of AKI occurrence in patients with gastrointestinal and hepatobiliary surgery in ICU. NLR should be included in the routine assessment of AKI occurrence.