title: Risk factors for recurrence after acute colonic diverticulitis: a systematic review.
abstract: OBJECTIVE
  Several factors may influence the risk of recurrence after an episode of acute colonic diverticulitis. Until now, a comprehensive systematic overview and evaluation of relevant risk factors have not been presented. This review aimed at assembling and evaluating current evidence on risk factors for recurrence after conservatively treated acute colonic diverticulitis.
  
  
  METHODS
  PubMed, Embase, and Cochrane databases were searched for studies evaluating risk factors for recurrence after acute diverticulitis treated non-surgically defined as antibiotic treatment, percutaneous abscess drainage, or by observation. Randomized clinical trials and observational studies were included. Analyzed outcome variables were extracted and grouped. No meta-analysis was performed due to low inter-study comparability. Variables were rated according to their likelihood of causing recurrence (no/low, medium, high).
  
  
  RESULTS
  Of 1153 screened records, 35 studies were included, enrolling 396,676 patients with acute diverticulitis. A total of 50,555 patients experienced recurrences. Primary diverticulitis with abscess formation and young age increased the risk of recurrence. Readmission risk was higher within the first year after remission. In addition, the risk of subsequent diverticulitis more than doubled after two earlier episodes of diverticulitis and the risk increased further for every episode.
  
  
  CONCLUSIONS
  The best treatment strategy for recurrent diverticulitis is undetermined. However, the risk of a new recurrence seemed to increase after each recurrence making elective resection a viable option at some point after multiple recurrences depending on patient risk factors and preferences.
authors.affiliation: Department of Surgery, Herlev Hospital, University of Copenhagen, Herlev, Denmark. linehupfeld01@gmail.com.
authors.forename: Line
authors.identifier: http://orcid.org/0000-0002-5865-2939
authors.initials: L
authors.lastname: Hupfeld
authors.affiliation: Department of Surgery, Zealand University Hospital, University of Copenhagen, Køge, Denmark.
authors.forename: Jakob
authors.initials: J
authors.lastname: Burcharth
authors.affiliation: Department of Surgical Gastroenterology, Rigshospitalet, University of Copenhagen, Copenhagen, Danmark.
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Pommergaard
authors.affiliation: Department of Surgery, Herlev Hospital, University of Copenhagen, Herlev, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Rosenberg
mesh_terms: D000038:Abscess / Q000473:pathology; D000208:Acute Disease; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D004239:Diverticulitis, Colonic / Q000209:etiology* / Q000517:prevention & control / Q000601:surgery; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012307:Risk Factors; D013997:Time Factors
keywords: Acute diverticulitis; Readmission; Recurrence; Risk factors