AIM: To determine the outcome of patients with biliary fistula (BF) after treatment for hydatid disease of the liver. METHODS: Between January 2000 and December 2010, out of 301 patients with a diagnosis of hydatid cyst of the liver, 282 patients who underwent treatment [either surgery or puncture, aspiration, injection and reaspiration (PAIR) procedure] were analysed. Patients were grouped according to the presence or absence of postoperative biliary fistula (PBF) (PBF vs no-PBF groups, respectively). Preoperative clinical, radiological and laboratory characteristics, operative characteristics including type of surgery, peroperative detection of BF, postoperative drain output, morbidity, mortality and length of hospital stays of patients were compared amongst groups. Multivariate analysis was performed to detect factors predictive of PBF. Receiver operative characteristics (ROC) curve analysis were used to determine ideal cutoff values for those variables found to be significant. A comparison was also made between patients whose fistula closed spontaneously (CS) and those with intervention in order to find predictive factors associated with spontaneous closure. RESULTS: Among 282 patients [median (range) age, 23 (16-78) years; 77.0% male]; 210 (74.5%) were treated with conservative surgery, 33 (11.7%) radical surgery and 39 (13.8%) underwent percutaneous drainage with PAIR procedure A PBF developed in 46 (16.3%) patients, all within 5 d after operation. The maximum cyst diameter and preoperative alkaline phosphatase levels (U/L) were significantly higher in the PBF group than in the no-PBF group [10.5 ± 3.7 U/L vs 8.4 ± 3.5 U/L (P < 0.001) and 40.0 ± 235.1 U/L vs 190.0 ± 167.3 U/L (P = 0.02), respectively]. Hospitalization time was also significantly longer in the PBF group than in the no-PBF group [37.4 ± 18.0 d vs 22.4 ± 17.9 d (P < 0.001)]. A preoperative high alanine aminotransferase level (> 40 U/L) and a peroperative attempt for fistula closure were significant predictors of PBF development (P = 0.02, 95%CI: -0.03-0.5 and P = 0.001, 95%CI: 0.1-0.4), respectively. Comparison of patients whose PBF CS or with biliary intervention (BI) revealed that the mean diameter of the cyst was not significantly different between CS and BI groups however maximum drain output was significantly higher in the BI group (81.6 ± 118.1 cm vs 423.9 ± 298.4 cm, P < 0.001). Time for fistula closure was significantly higher in the BI group (10.1 ± 3.7 d vs 30.7 ± 15.1 d, P < 0.001). The ROC curve analysis revealed cut-off values of a maximum bilious drainage < 102 mL and a waiting period of 5.5 postoperative days for spontaneous closure with the sensitivity and specificity values of (83.3%-91.1%, AUC: 0.90) and (97%-91%, AUC: 0.95), respectively. The multivariate analysis demonstrated a PBF drainage volume < 102 mL to be the only statistically significant predictor of spontaneous closure (P < 0.001, 95%CI: 0.5-1.0). CONCLUSION: Patients with PBF after hydatid surgery often have complicated postoperative course with serious morbidity. Patients who develop PBF with an output < 102 mL might be managed expectantly. © 2013 Baishideng. All rights reserved.