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

BACKGROUND

Patients 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.

METHODS

575 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.

RESULTS

Child-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-naïve patients undergoing paracentesis and presenting with PMN-counts ≥100 cells/μl, or hyponatraemia <125 mM 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 MELD≥22, CRP ≥3.5 mg/dl and development of grade III/IV hepatic encephalopathy showed highest mortality.

CONCLUSIONS

Low serum sodium levels, Child-Pugh stage C and elevated ascites PMN counts (≥100 cells/μl) indicate a significant risk for SBP development. SBP-related mortality is highest in patients with MELD≥22 and elevated CRP levels.