The impact of bacterial infection on the risk of portal vein thrombosis development in patients with cirrhosis: a post-hoc analysis

Background: Portal vein thrombosis (PVT) is a common complication in liver cirrhosis. Bacterial infections (BIs) may increase PVT risk through bacterial translocation, systemic inflammation, and coagulation dysfunction, but evidence is limited. Aims: This study investigates the 6-month risk of onset of PVT in patients hospitalized with BIs. Methods: This post-hoc analysis included 563 cirrhotic patients hospitalized between 2011 and 2021, with or without BIs diagnosis, and followed for 6 months post-discharge. Patients with HCC outside of Milan criteria were excluded. The main endpoint was the onset of PVT, diagnosed via abdominal ultrasound or CT/MRI. Results: BI was diagnosed in 146 patients (26 %). Forty-seven patients (8.5 %) experienced PVT events within 6 months, including 15 (10 %) with BIs and 32 (7.8 %) without (p = 0.4). Logistic regression showed no significant effect of BI on PVT occurrence (OR 1.35, 95 % CI 0.69–2.54), even after adjusting for confounding factors. However, urinary tract infections were independently associated with higher PVT risk (OR 3.17, 95 % CI 1.05–10.8, p = 0.048). Other infection sites (pneumonia, spontaneous bacterial peritonitis-SBP, spontaneous bacteremia) and isolated microbial strains (n = 77) were not associated with increased PVT risk. When analyzing the population excluding patients with HCC, the risk of developing PVT was significantly higher in patients with previous BI, regardless of the severity of liver disease (OR 2.92, 95 % CI 1.06–8.16). Conclusions: In this large cohort, BIs did not significantly increase PVT risk within 6 months post-hospitalization in cirrhotic patients. However, when the cohort was reduced to patients without HCC, the risk of PVT appears to be significant.