title: Risk factors for ischaemic colitis after surgery for abdominal aortic aneurysm: a systematic review and observational meta-analysis.
abstract: BACKGROUND
  Ischaemic colitis is an infrequent but serious complication following repair of abdominal aortic aneurysm (AAA), with high mortality rates. This systematic review set out to identify risk factors for the development of ischaemic colitis after AAA surgery.
  
  
  METHODS
  A systematic search of the MEDLINE, EMBASE and CINAHL databases was performed. This search was limited to studies published in the English language after 1990. Abstracts were screened by two authors. Eligible studies were obtained as full text for further examination. Data was extracted by two authors, and any disputes were resolved via consensus. Extracted data was pooled using Mantel-Haenszel random effects models. Bias was assessed using two Cochrane-approved tools. Effect sizes are expressed as relative risk ratios alongside the 95 % confidence interval. Statistical significance was defined at the level of p < 0.05.
  
  
  RESULTS
  From 388 studies identified in the initial search, 33 articles were included in the final synthesis and analysis. Risk factors were grouped into patient (female gender, disease severity) and operative factors (peri-procedural hypotension, operative modality). The risk of ischaemic colitis was significantly higher when undergoing emergency repair versus elective (risk ratio (RR) 7.36, 3.08 to 17.58, p < 0.001). Endovascular repair reduced the likelihood of ischaemic colitis (RR 0.22, 0.12 to 0.39, p < 0.001).
  
  
  CONCLUSIONS
  The quality of published evidence on this subject is poor with many retrospective datasets and inconsistent reporting across studies. Despite this, emergency presentation and open repair should prompt close monitoring for the development of IC.
authors.affiliation: Department of General Surgery, Northern General Hospital, First Floor, Old Nurses Home Herries Road, Sheffield, UK, S5 7AU. M.J.Lee@sheffield.ac.uk.|Department of Oncology & Metabolism, University of Sheffield, Sheffield, UK. M.J.Lee@sheffield.ac.uk.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Lee
authors.affiliation: Department of General Surgery, Northern General Hospital, First Floor, Old Nurses Home Herries Road, Sheffield, UK, S5 7AU.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Daniels
authors.affiliation: Department of Oncology & Metabolism, University of Sheffield, Sheffield, UK.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Drake
authors.affiliation: Department of General Surgery, Northern General Hospital, First Floor, Old Nurses Home Herries Road, Sheffield, UK, S5 7AU.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Adam
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000150:complications* / Q000601:surgery*; D017091:Colitis, Ischemic / Q000150:complications* / Q000601:surgery*; D006801:Humans; D064887:Observational Studies as Topic; D017594:Publication Bias; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors
keywords: Abdominal aortic aneurysm; Ischaemic colitis; Outcomes