Older age, longer procedures and tandem endoscopic-ultrasound as risk factors for post-endoscopic retrograde cholangiopancreatography bacteremia.

Background: Clinically significant post-endoscopic retrograde cholangiopancreatography (ERCP) bacteremia (PEB) occurs in up to 5% of cases, while antibiotic prophylaxis is recommended only when an ERCP is unlikely to achieve complete biliary drainage. However, the current recommendations may not cover all potential risk factors for PEB.

Aim: To identify novel risk factors for PEB and evaluate appropriateness of antibiotic prophylaxis.

Methods: A retrospective study of 1082 ERCP procedures performed between January 2012 - December 2013 in a single tertiary medical center. Data collection included: Demographic and clinical characteristics such as pre and post procedure antibiotic treatment and bacterial blood cultures. Exclusion criteria were: (1) Age < 18 years; (2) Positive bacterial blood culture before ERCP; (3) Scheduled antibiotic treatment prior to ERCP; (4) Hospitalization longer than 14 d before ERCP; and (5) missing critical data. Stepwise Logistic Regression analysis and Decision Tree algorithms were used for prediction modeling of PEB.

Results: A total of 626 ERCPs performed in 434 patients were included. Mean age 66.49 ± 15.4 years and 46.5% were males. PEB prevalence was 3.7%. Antibiotic prophylaxis was administrated in 139/626 (22.2%) cases but was indicated according to the guidelines only in 44/626 (7%) cases. In all the PEB cases, prophylaxis was deemed not indicated. A stepwise logistic regression [receiver operating characteristic (ROC), 0.766], identified 3 variables as independent risk factors for PEB: Age at ERCP ≥ 75 years (OR, 3.780, 95%CI: 1.519-9.408, = 0.004); Tandem EUS/ERCP with fine needle aspiration (FNA) (OR, 14.528, 95%CI: 3.571-59.095, < 0.001); ERCP duration longer than 60 min (OR, 5.396, 95%CI: 1.86-15.656, = 0.002). In a decision tree model (ROC, 0.778) the probability for PEB without any risk factors was 1% regardless of prophylaxis administration.

Conclusion: The prevalence of PEB in our study is similar to previous reports, despite the fact that antibiotic prophylaxis was administrated more readily than recommended. ERCP duration longer than 60 min, tandem EUS-ERCP with FNA and age above 75 years are significant risk factors for PEB. These factors should be further evaluated as indications for prophylactic antibiotic treatment before ERCP.