Abstract: Objective The aim of this study was to explore the evaluation of bacterial infection by common hematological indexes in patients with acute-on-chronic liver failure (ACLF). Methods 208 patients with ACLF were admitted to our hospital between July 2015 and July 2022, and were given conventional supporting therapy. The clinical materials of all patients were retrospectively analyzed. The factors impacting bacterial infection was evaluated by binary multivariate Logistic analysis. The judging performance of infection by each index was evaluated by receiver operating characteristic (ROC) curves, and the Cox regression analysis was applied to predict the prognosis. Results Out of the 208 patients with ACLF in our series,the incidence of bacterial infection was 68.8%, and the common infection sites were abdominal infection in 87 cases(51.5%), pulmonary infection in 38 cases (22.5%), urinary tract infection in 4 cases (2.4%), blood infection in 1 case (0.6%) and other site infection in 39 cases (23.0%), and there were 119 cases with single site infection and 24 cases with multi-site infection; 108 patients (51.9%) were discharged recovered, and 100 patients (48.1%) died during hospitalization or after discharge; the average age in patients with bacterial infection was (48.4±12.6) years, significantly greater than in those without infection [(43.9±12.4) years, P<0.05]; the white blood cells (WBC) count, neutrophil count and serum procalcitonin (PCT) level in patients with infection were 7.0 (4.8, 8.9)×10⁹/L, 5.0 (3.3,6.7)×10⁹/L and 0.9 (0.4,1.2) ng/ml, all significantly higher than [6.0 (4.6, 7.3)×10⁹/L, 4.1 (2.9, 5.1)×10⁹/L and 0.5 (0.3, 0.9) ng/ml, respectively, P＜0.05] in those without infection, while there were no significant differences as respect to serum C-reaction protein (CRP) and hypersensitive C-reactive protein (hsCRP) levels in the two groups (P > 0.05); serum total bilirubin (TBIL), international standardization ratio (INR) and D-dimer levels were significantly higher than those in patients without infection (P<0.05), while blood red blood cell (RBC) count, hemoglobin (Hb), albumin, ALT, AST, cholinesterase, Na⁺, PTA and alpha fetoprotein (AFP) in patients with infection were significantly lower than those in patients without infection (P<0.05); the Logistic analysis showed that Hb, neutrophil count, TBIL, Na⁺ and PTA were the independent influencing factors for bacterial infection in patients with ACLF; the ROC curves analysis showed that the AUCs were 0.645, 0.627, 0.724, 0.658 and 0.645 by Hb, neutrophil count, TBIL, Na⁺ and PTA, predicting bacterial infection in patients with ACLF, when the cut-off-value were set as 117.5 g/L, 5.1×10⁹/L, 261.0 μmol/L, 137.5 mmol/L and 34.5%, while the combination of the above indicators had the largest AUC of 0.810, with the sensitivity and specificity of 70.6% and 79.4%, respectively; the Cox multivariate analysis showed that TBIL and PTA were the independent risk factors for the poor prognosis of patients with ACLF. Conclusion Under the circumstance of ACLF, some common blood parameters might help judge infection, and warrants emphasis in clinical practice.

Key words: Acute-on-chronic liver failure, Bacterial infection, Hematological index, Serum index, Auxiliary diagnosis, Prognosis