Ammonia is associated with liver-related complications and predicts mortality in acute-on-chronic liver failure patients.

Abstract

Abstract Background and aims: The relationship between ammonia and liver-related complications (LRCs) in acute-on-chronic liver failure (ACLF) patients is not well defined. This study aimed to evaluate the association of ammonia levels with LRCs in patients with ACLF. The study also evaluated the role of ammonia in predicting mortality and progression of LRCs. Methods: ACLF patients using the APASL definition were prospectively recruited from the ACLF Research Consortium (AARC) between 2009 and 2019. A total of 3,871 cases were recruited, with most subjects caused by alcohol and HBV infection. Patients with baseline ammonia were enrolled for analysis. LRCs were a composite endpoint of bacterial infection, overt HE, and ascites. Results: A total of 701 ACLF patients were enrolled. Ammonia levels were significantly higher in patients with LRCs than those without. Ammonia was significantly higher in ACLF patients with overt HE and ascites, but not in those with bacterial infection. Multivariate analysis revealed that AARC score, and ammonia were independently associated with LRCs. Within a month after admission, 350 patients (49.9%) died. Multivariate analysis demonstrated that older age, low haemoglobin, high INR, creatinine, ALT, and ammonia levels were independent predictors of 30-day mortality. Baseline ammonia ≥ 78 µmol/L was independently related to LRCs with an AUROC of 0.74 (p<0.001). Patients who had ammonia ≥ 78 µmol/L faced a higher risk of death within 30 days. Conclusions: In ACLF patients, baseline arterial ammonia levels are associated with LRCs, mainly overt HE and ascites. Ammonia was also an independent predictor of 30-day mortality.