Effect of abdominal fat distribution on severity of acute pancreatitis

Introduction
Obesity is a well-determined risk factor for acute pancreatitis. Increased visceral fat has been shown to increase the proinflammatory environment experienced by patients. In this study, we aimed to research the correlation between abdominal fat distribution parameters measured with computed tomography (CT) and severity of acute pancreatitis (AP).

Material and methods
The study included patients monitored due to AP in the internal medicine clinic of GOP Education and Research Hospital from January 2015 to December 2018. The Acute Physiology and Chronic Health Evaluation (APACHE) score, the Imrie score and the Bedside Index of Severity in Acute Pancreatitis (BISAP) scores were calculated. Advanced image processing analysis software (INFINIT Xelis, v 1.0.6.3) was used to calculate individual abdominal fat distribution parameters from CT screening with division of abdominal tissues. Measurements were performed from –50 to –250 Hounsfield units (HU) between vertebrae L2-L3.

Results
When mild and moderate AP groups were compared, there were statistically significant differences in duration of hospital stay and scoring (APACHE, Imrie and BISAP) (p < 0.001), while there were no significant differences in abdominal fat distribution parameters (p > 0.05). There was no significant correlation of visceral and subcutaneous fat volumes with development of systemic complications, while a significant correlation was identified for visceral to total fat tissue area ratio (VTR) with local complications (p < 0.001). Pearson correlation analysis found no correlations of mortality and pancreatitis severity with visceral (VFA) and subcutaneous fat area (SFA) (p > 0.05). Positive correlations were identified for VFA with Imrie, BISAP and APACHE scores (p < 0.01), and positive correlations were identified for visceral adipose tissue (VAT) with visceral to subcutaneous fat ratio (VSR) and APACHE scores (r = 0.256 and 0.252, respectively, p < 0.001). Positive correlations were identified for VTR and VSR ratios with BISAP scores (r = 0.266 and r = 0.277, respectively, p < 0.001).

Conclusions
In patients with AP diagnosis and abdominal CT scans, increased VFA and VTR ratio were found to be associated with increased AP clinical scores with no significant correlation identified in terms of local/systemic complication development. Our study shows that VFA is linked to AP clinical scoring systems and should be included in AP predictive scoring systems.