Aim of the study: We aimed to investigate the possible association between serum copeptin and complications

of liver cirrhosis, including its potential role as a stress biomarker in spontaneous bacterial peritonitis (SBP).

Material and methods: This cross-sectional study included 89 cirrhotic ascitic patients (37 with SBP and 52 without

SBP) admitted to Sohag University Hospitals, Egypt, between June 2021 and February 2022. Serum copeptin

was measured in all patients, and its association with SBP and other complications of liver cirrhosis was investigated.

Results: Serum copeptin was significantly elevated in patients with SBP compared to those without SBP

(p = 0.032) and significantly correlated with ascitic fluid study parameters, systemic inflammatory markers, and

liver, renal, and circulatory functions. Serum copeptin and C-reactive protein (CRP) were independent risk factors

for the presence of SBP. Serum copeptin detects SBP at a cut-off value of 9 pmol/l, with sensitivity and specificity

of 73% and 64%, respectively. Serum copeptin was significantly associated with hepatic encephalopathy, gastrointestinal

bleeding, hepatorenal syndrome, and larger amounts of ascites.

Conclusions: Serum copeptin is an independent risk factor for the presence of SBP and significantly increased

in patients presented with major complications of liver cirrhosis, demonstrating its ability to reflect circulatory

dysfunction and systemic inflammation.