Splanchnic vein thrombosis (2003-2022): a Swiss nationwide epidemiological study

Splanchnic vein thrombosis (SVT) is a rare form of venous thromboembolism with limited epidemiological data. This study aims to provide a detailed overview in Switzerland using administrative records.

We analysed nationwide patient-level data on SVT-related hospitalizations, including portal, splenic, and hepatic (Budd-Chiari syndrome) vein thrombosis from 2003 to 2022. We assessed trends in crude and age-standardized incidence rates, proportion of SVT-related hospitalizations, readmission rates as well as gender differences, comorbidities, clinical features, and in-hospital outcomes. Multivariable logistic regression was used to identify predictors of in-hospital death.

SVT was recorded in 17,966 hospitalizations (35 % women) involving 13,689 patients. Portal vein thrombosis was the most frequent manifestation, followed by splenic, hepatic and multisegmental thrombosis. Age-standardized incidence rate increased from 0.4 (95 % CI: 0.3-0.4) per 10,000 general population in 2003 to 1.5 (95 % CI: 1.4-1.6) in 2022, with rising proportions of SVT-related hospitalizations and readmission rates. Case fatality rate remained steady at 13 % and was highest for portal vein thrombosis. For most SVT subtypes, incidence rate was higher in males and case fatality rate in females. Predictors of in-hospital death included liver failure, intestinal infectious diseases, cancer. Common comorbidities included non-neoplastic abdominal diseases (14,010; 78 %), cardiovascular diseases (11,214; 62 %), and cancer (8510; 47 %). Diagnostic or therapeutic procedures involved 56 % of cases, intensive care stay 19 %, and median length of stay was 11 days (Q1-Q3 5-19).

Despite its rarity, SVT is characterized by substantial morbidity and in-hospital mortality. Further research is needed to validate these findings and improve patient management.