title: The effect of NOD2 polymorphism on postsurgical recurrence in Crohn's disease: a systematic review and meta-analysis of available literature.
abstract: BACKGROUND
  Up to 70% of patients requiring surgery for Crohn's disease (CD) develop recurrence within 10 years. Unequivocal markers predicting recurrence are needed to tailor postoperative therapy appropriately. NOD2 (nucleotide-binding oligomerization domain 2) polymorphisms increase the risk of developing CD; however, their ability to predict recurrence is uncertain. This study aims to determine the association between NOD2 variants and surgical recurrence after initial disease-modifying surgery.
  
  
  METHODS
  A comprehensive search for published series comparing the effect of NOD2 polymorphisms on postoperative surgical recurrence in patients with CD was performed. Random-effects methods were used to combine data.
  
  
  RESULTS
  Six cohort studies comprising 1003 patients with CD were included. A total of 340 patients (33.9%) expressed at least 1 of the 3 common NOD2 polymorphisms. The 1003 patients underwent surgical resection with 335 (33%) developing surgical recurrence. Of 340 NOD2-expressing patients, 130 (39%) required further resection, whereas 202 of 663 patients (30.5%) without the variant underwent repeat resection. NOD2 was not significantly associated with surgical recurrence (odds ratio: 1.58, 95% confidence interval: 0.97-2.57, P = 0.064), most likely because of study heterogeneity (Cochran Q: 12.36, P = 0.030, I: 59.6%). The sensitivity of any mutation in predicting disease recurrence was 39.7% and specificity was 69%, with the area under the receiver operating characteristic curve being 0.64.
  
  
  CONCLUSIONS
  Patients with CD with a NOD2 polymorphism do not have an increased risk of surgical recurrence compared with patients without the variant. These data provide insufficient evidence to support postoperative medical prophylaxis based solely on the presence of NOD2 polymorphism.
authors.affiliation: Department of Surgery, University Hospital Limerick, Limerick, Ireland.
authors.forename: Jacqueline G
authors.initials: JG
authors.lastname: Solon
authors.forename: John P
authors.initials: JP
authors.lastname: Burke
authors.forename: Stewart R
authors.initials: SR
authors.lastname: Walsh
authors.forename: J Calvin
authors.initials: JC
authors.lastname: Coffey
mesh_terms: D006801:Humans; D015331:Cohort Studies; D003424:Crohn Disease / Q000150:complications / Q000235:genetics / Q000601:surgery; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics; D011183:Postoperative Complications; D011379:Prognosis; D012008:Recurrence
chemical_list: C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein