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.