title: Retention associated with video capsule endoscopy: systematic review and meta-analysis.
abstract: OBJECTIVE
  Video capsule endoscopy (VCE) has become a major diagnostic tool for small-bowel evaluation. However, retention of the video capsule endoscope remains a major concern.
  
  
  METHODS
  We performed a systematic review of VCE retention rates by using Pubmed and SCOPUS (1995-2015). We included studies that enrolled at least 10 patients, included VCE retention rates, and separated retention rates by indication. We used Comprehensive Meta-Analysis (Version 3.0) to calculate pooled prevalence rates with 95% confidence intervals (CIs) and assessed heterogeneity by using the Cochran Q statistic.
  
  
  RESULTS
  We included 25 studies (N = 5876) for patients undergoing VCE for evaluation of potential small-bowel bleeding, 9 studies (N = 968) for patients with suspected inflammatory bowel disease (IBD), 11 studies (N = 558) for patients with established IBD, and 8 studies for patients (N = 111) undergoing VCE for evaluation of abdominal pain and/or diarrhea. We used a random effects model and found that the pooled retention rate was 2.1% for patients with suspected small-bowel bleeding (95% CI, 1.5%-2.8%). Retention rates were 3.6% (95% CI, 1.7%-8.6%) for suspected IBD, 8.2% (95% CI, 6.0%-11.0%) for established IBD, and 2.2% (95% CI, 0.9%-5.0%) for abdominal pain and/or diarrhea. Based on subgroup analysis, subsequent VCE completion rates after performance of a patency capsule or CT enterography in patients with IBD to exclude retentions due to strictures was 2.7% (95% CI, 1.1%-6.4%). Reasons for retention were provided in 60 (77%) studies. The most common reasons for retention were small-bowel strictures, although etiology was not provided in all studies.
  
  
  CONCLUSIONS
  VCE retention occurs in approximately 2% of patients undergoing evaluation for small-bowel bleeding and is most likely due to small-bowel strictures. Retention rates in patients with suspected or known IBD were approximately 4% and 8%, based on our meta-analysis. These rates decreased by half in those studies that used either a patency capsule or CT enterography to assess patency before performing VCE.
authors.affiliation: Division of Gastroenterology, California Pacific Medical Center, San Francisco, California, USA.
authors.forename: Mona
authors.initials: M
authors.lastname: Rezapour
authors.affiliation: Department of Medicine, King's College, London, England.
authors.forename: Chidi
authors.initials: C
authors.lastname: Amadi
authors.affiliation: Division of Gastroenterology, California Pacific Medical Center, San Francisco, California, USA; Division of Medicine, University of California San Francisco, San Francisco, California, USA.
authors.forename: Lauren B
authors.initials: LB
authors.lastname: Gerson
mesh_terms: D053705:Capsule Endoscopes; D053704:Capsule Endoscopy / Q000009:adverse effects*; D003251:Constriction, Pathologic / Q000150:complications; D005547:Foreign Bodies / Q000453:epidemiology* / Q000209:etiology; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis*; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis*; D007410:Intestinal Diseases / Q000150:complications; D007421:Intestine, Small