Thiopurine Therapy Is Associated with Postoperative Intra-Abdominal Septic Complications in Abdominal Surgery for Crohn's Disease

PURPOSE: Thiopurines are important as maintenance therapy in Crohn's disease, but there have been concerns whether thiopurines increase the risk for anastomotic complications. The present study was performed to assess whether thiopurines alone, or together with other possible risk factors, are associated with postoperative intra-abdominal septic complications after abdominal surgery for Crohn's disease. METHODS: Prospectively registered data regarding perioperative factors were collected at a single tertiary referral center from 1989 to 2002. Data from 343 consecutive abdominal operations on patients with Crohn's disease were entered into a multivariate analysis to evaluate risk factors for intra-abdominal septic complications. All operations involved either anastomoses, strictureplasties, or both; no operations, however, involved proximal diversion. RESULTS: Intra-abdominal septic complications occurred in 26 of 343 operations (8%). Thiopurine therapy was associated with an increased risk of intra-abdominal septic complications (16% with therapy; 6% without therapy; P = 0.044). Together with established risk factors such as pre-operative intra-abdominal sepsis (18% with sepsis; 6% without sepsis; P = 0.024) and colocolonic anastomosis (16% with such anastomosis; 6% with other types of anastomosis; P = 0.031), thiopurine therapy was associated with intra-abdominal septic complications in 24% if any 2 or all 3 risk factors were present compared with 13% if any 1 factor was present, and only 4% in patients if none of these factors were present (P < 0.0001). CONCLUSIONS: Thiopurine therapy is associated with postoperative intra-abdominal septic complications. The risk for intra-abdominal septic complications was related to the number of identified risk factors. This increased risk should be taken into consideration when planning surgery for Crohn's disease.