Risk of a first community-acquired spontaneous bacterial peritonitis in cirrhotics with low ascitic fluid protein levels

Background & Aims: Long-term primary antibiotic prophylaxis of spontaneous bacterial peritonitis has been suggested to be useful in cirrhotic patients with low ascitic fluid protein levels. However, it is unlikely that all su ch patients need prophylactic treatment. The aim of this study was to ident ify the group of cirrhotic patients with low ascitic fluid protein levels a t high risk of developing a first episode of spontaneous bacterial peritoni tis during outpatient follow-up. Methods: One hundred nine cirrhotic patien ts with low ascitic fluid protein levels and without previous episodes of s pontaneous bacterial peritonitis were followed up in an outpatient clinic. Results: Twenty-eight patients developed a first spontaneous bacterial peri tonitis episode. In the multivariate analysis, serum bilirubin level (>3.2 mg/dL) and platelet count (<98.000/mm(3)) independently correlated with the risk of developing the first spontaneous bacterial peritonitis (P < 0.01 a nd P < 0.05, respectively). According to the median relative risk coefficie nt, a low-risk group (relative risk <1.09) and a high-risk group (relative risk >1.09) were established. The probability of developing a first spontan eous bacterial peritonitis episode at 1-year follow-up was significantly hi gher in the high risk-group (low-risk group, 23.6%; high-risk group, 55%; P < 0.01) as a consequence of a higher probability of the first community-ac quired episode (13.7% vs. 47.6%, respectively, P < 0.01). One-year probabil ity of survival was significantly lower in the high-risk group (low-risk gr oup, 57.6%; high-risk group, 38%, P < 0.05). Conclusions: Cirrhotic patient s with low ascitic fluid protein levels (less than or equal to 1 g/dL) and high bilirubin level and/or low platelet count are at high risk of developi ng a first episode of spontaneous bacterial peritonitis during long-term fo llow-up.