BACKGROUND AND AIMS: Visceral adipose tissue has been indicated closely connected with the severity of acute pancreatitis (AP). Visceral adiposity index (VAI) is a mathematical model that consists of waist circumference, body mass index, triglyceride and high-density lipoprotein cholesterol, which has been demonstrated to be a better indicator of visceral fat than other traditional indices. This study aimed to evaluate the relationship between VAI and the severity of AP. METHODS: A retrospective analysis was conducted on a cohort of 1174 patients diagnosed with AP. These patients were categorized into two groups based on their VAI values: the normal VAI (NVAI) group and the elevated VAI (EVAI) group. RESULTS: The EVAI group were much younger, mainly male and had higher incidence of severe acute pancreatitis (SAP) compared with the NVAI group (p <
0.001). The EVAI group developed higher incidences of persistent respiratory failure, acute peripancreatic fluid collection (APFC) and acute necrotic collection (ANC). The VAI level and the percentage of EVAI showed an increasing trend with the severity of AP (p <
0.001). EVAI was the most independent risk factor for persistent respiratory failure (OR = 6.405, 95% CI 2.317-17.705), APFC (OR = 2.093, 95% CI 1.255-3.578) and ANC (OR = 4.910, 95% CI 1.736-13.887). CONCLUSIONS: EVAI was strongly related to the severity of AP. It was the most independent risk factor of persistent respiratory failure, APFC and ANC.