New Risk Factors for Infected Pancreatic Necrosis Secondary to Severe Acute Pancreatitis: The Role of Initial Contrast-Enhanced Computed Tomography

Background and Aims Pancreatic necrosis is a risk factor for poor prognosis of acute pancreatitis (AP). However, the associations between the findings on initial contrast-enhanced computed tomography (CT) of the pancreas and infected pancreatic necrosis (IPN) are unclear. Methods This was a retrospective cohort study. Patients with severe AP (SAP) from January 2014 to December 2016 at the First Affiliated Hospital of Nanchang University were enrolled and assigned to an IPN group and a non-IPN group. Univariate and multivariate logistic regression analyses were sequentially performed to assess the associations between the variables and IPN development. A receiver operating characteristic (ROC) curve was generated for the qualified independent risk factor. Results Forty-two patients with IPN were compared with 100 patients without IPN. Contrast-enhanced CT was performed 7 (range 3–10) days after AP onset. Multivariate stepwise logistic regression analyses showed that the number of acute peripancreatic fluid collections (APFCs) (OR 1.328, P = 0.006), presence of peripancreatic and pancreatic parenchymal necrosis (OR 4.001, P = 0.001), and gastrointestinal wall thickening (OR 3.353, P = 0.006) were independent risk factors for IPN secondary to SAP. The area under an ROC curve for the number of APFCs was 0.714, the sensitivity was 78.60%, and the specificity was 57.30% at a cutoff value of 4.5. Conclusions The number of APFCs, presence of peripancreatic and pancreatic parenchymal necrosis, and gastrointestinal wall thickening were independent risk factors associated with IPN. As initial contrast-enhanced CT (about 7 days from AP onset) plays an important role in predicting IPN, it is important for clinicians to consider initial imaging of the pancreas.