Factors associated with surgery in patients with intra-abdominal fistulizing Crohn's disease

AIM: To characterize radiological and clinical factors associated with subsequent surgical intervention in Crohn’s disease (CD) patients with intra-abdominal fistulae. METHODS: From a cohort of 1244 CD patients seen over an eight year period (2006 to 2014), 126 patients were identified as having intra-abdominal fistulae, and included in the study. Baseline patient information was collected from the medical records. Imaging studies were assessed for: anatomic type and number of fistulae; diameter of the inflammatory conglomerate; length of diseased bowel; presence of a stricture with pre-stenotic dilatation; presence of an abscess; lymphadenopathy; and the degree of bowel enhancement. Multivariate analysis for the prediction of abdominal surgery was calculated via Generalized Linear Models. RESULTS: In total, there were 193 fistulae in 132 patients, the majority (52%) being entero-enteric. Fifty-nine (47%) patients underwent surgery within one year of the imaging study, of which 36 (29%) underwent surgery within one month. Radiologic features that were associated with subsequent surgery included: multiple fistulae (P = 0.009), presence of stricture (P = 0.02), and an entero-vesical fistula (P = 0.01). Evidence of an abscess, lymphadenopathy, or intense bowel enhancement as well as C-reactive protein levels was not associated with an increased rate of surgery. Patients who were treated after the imaging study with combination immunomodulatory and anti-TNF therapy had significantly lower rates of surgery (P = 0.01). In the multivariate analysis, presence of a stricture [RR 4.5 (1.23-16.3), P = 0.02] was the only factor that increased surgery rate. CONCLUSION: A bowel stricture is the only factor predicting an increased rate of surgery. Radiological parameters may guide in selecting treatment options in patients with fistulizing CD.