Risk factors for development of spontaneous bacterial peritonitis and subsequent mortality in cirrhotic patients with ascites

BackgroundPatients with ascites are at risk for developing spontaneous bacterial peritonitis (SBP) - a severe complication associated with high mortality. We aimed to identify risk factors for SBP development and mortality to optimize stratification for primary prophylaxis and therapeutic strategies to improve survival. Methods575 patients with cirrhosis and ascites undergoing paracentesis at a tertiary care hospital were included in this retrospective cohort study. Demographical, clinical and laboratory parameters were recorded at first paracentesis and during follow-up. Multivariate logistic regression analysis was used to identify independent predictors of SBP development and mortality. ResultsChild-Pugh stage C (OR: 3.323; P=0.009), ascitic fluid polymorph-nuclear cell (PMN) count (OR: 1.544; P=0.028) and low serum sodium (OR: 0.917; P=0.029) emerged as independent risk factors for SBP development. SBP-naive patients undergoing paracentesis and presenting with PMN-counts 100cells/l, or hyponatraemia <125mM were at highest risk for developing SBP. Increases in MELD and CRP levels indicated SBP development, while no changes where observed in a matched control group with sterile ascites at multiple paracenteses. MELD score (OR: 1.565; P=0.001) and CRP (OR: 1.067; P=0.037) were identified as independent risk factors for 30-day mortality after SBP diagnosis. In particular SBP patients with MELD22, CRP 3.5mg/dl and development of grade III/IV hepatic encephalopathy showed highest mortality. ConclusionsLow serum sodium levels, Child-Pugh stage C and elevated ascites PMN counts (100cells/l) indicate a significant risk for SBP development. SBP-related mortality is highest in patients with MELD22 and elevated CRP levels.