Predictors of Spontaneous Bacterial Peritonitis in Patients with Cirrhotic Ascites

Spontaneous bacterial peritonitis (SBP) is a serious complication of liver cirrhosis and a prognostic model to predict it is needed. This study was designed to test the ability of different laboratory tests and the new scoring system by Wehmeyer and colleagues (consisting of age, C-reactive protein (CRP) and platelet count) to predict it. Three-hundred patients admitted to the National Liver Institute, University of Menoufia, Egypt (2015-2016) with liver cirrhosis and ascites were included in our study. SBP was diagnosed if ascetic neutrophil count was ≥250/µL with no sign of secondary peritonitis. The patient population had age range of 29-81 years old, was 60% men and showed a majority (91.7%) with primary cause of liver disease being hepatitis C. By univariate analysis, associations with age, total bilirubin, aspartate aminotransferase level, creatinine level, international normalized ratio, model for end-stage liver disease score, total leucocytic count, platelet count and CRP level were significant. By multivariate analysis, independent predictors were age, platelet count and CRP level (p = 0.004, 0.013 and <0.001, respectively). CRP at a cut-off point ≥13.5 mg/L could predict SBP (sensitivity of 86.4% and specificity of 66.0%). Wehmeyer's SBP scoring system was predictive (p < 0.001); only 4% of patients with 0 score developed SBP (CRP cut-off of 30 mg/L), while 92.8% with score of 3 or 4 developed SBP. By using our modified Wehmeyer score with CRP cut-off value of 13.5 mg/L, no patient with 0 score developed SBP. Age, CRP level and platelet count are independent predictors for SBP and a scoring system including them could easily predict the condition. SBP diagnosis could be excluded in patients with 0 score, using CRP cut-off value of 13.5 mg/L.