Role of CT signs of thoracoabdominal complications, serum calcium, and serum C-reactive protein in evaluating disease severity in patients with acute pancreatitis

Objective To investigate the role of CT signs of thoracoabdominal complications, serum calcium, and serum C-reactive protein (CRP) in evaluating disease severity in patients with acute pancreatitis (AP) . Methods A retrospective analysis was performed for the results of thoracoabdominal CT and blood examination of 95 patients with AP who were treated in Characteristic Medical Center of Chinese People's Armed Police Force from December 2017 to December 2018. The patients were divided into severe AP (SAP) group with 13 patients and mild AP (MAP) group with 82 patients. The association of CT signs of thoracoabdominal complications, serum calcium, and serum CRP with the severity of AP was analyzed. The t-test was used for comparison of normally distributed continuous data between groups, and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between groups; the chi-square test was used for comparison of categorical data between groups. A logistic regression model was established based on the combination of related indices, and predicted probability was used as a new index for analysis; the receiver operator characteristic (ROC) curve was used to evaluate the effectiveness of each index in predicting disease severity. Results Compared with the MAP group, the SAP group had significantly higher incidence rates of ascites, pneumonia, and pleural effusion (χ2= 8. 561, 8. 120, and 9. 750, all P < 0. 05) , while there was no significant difference in the incidence rate of peritonitis between the two groups (P > 0. 05) . Compared with the MAP group, the SAP group had a significantly higher serum level of CRP (Z = 19. 16, P < 0. 05) , a significantly longer length of hospital stay (t = 3. 97, P < 0. 05) , and a significantly lower level of blood calcium (t = 4. 21, P < 0. 05) . The logistic regression analysis showed that ascites (odds ratio [OR] =4. 992, 95% confidence interval [CI]: 2. 087-6. 543, P = 0. 012) , pneumonia (OR = 1. 273, 95% CI: 1. 013-1. 520, P = 0. 042) , and pleural effusion (OR = 3. 521, 95% CI: 1. 080-4. 691, P = 0. 022) were independent risk factors for SAP, while peritonitis (OR =1. 007, 95% CI: 0. 990-1. 175, P = 0. 156) was not an independent risk factor. The ROC curve analysis showed that in the evaluation of disease severity, peritonitis, ascites, pneumonia, and pleural effusion had an area under the ROC curve (AUC) of 0. 635, 0. 738, 0. 714, and 0. 710, respectively, and the number of these CT signs had an AUC of 0. 807; serum calcium and CRP had an AUC of 0. 789 and0. 835, respectively, and serum calcium and CRP combined with the number of CT signs had an AUC of 0. 901. Conclusion Serum calcium and CRP combined with the number of thoracoabdominal CT signs (peritonitis, ascites, pneumonia, and pleural effusion) have high specificity, sensitivity, and accuracy in predicting disease severity in patients with AP, and therefore, it has a high clinical value and holds promise for clinical application.