title: Risk of readmission and emergency surgery following nonoperative management of colonic diverticulitis: a population-based analysis.
abstract: OBJECTIVE
  To characterize the clinical course of patients with diverticulitis after nonoperative management and determine factors associated with readmission and subsequent emergency surgery.
  
  
  BACKGROUND
  Clinical course of this disease remains poorly understood; indications for elective colectomy are unclear.
  
  
  METHODS
  This was a retrospective cohort study of patients managed nonoperatively after a first episode of diverticulitis in Ontario, Canada (2002-2012). Time-to-event analysis and Fine and Gray multivariable regression were used to characterize the risks of readmission and emergency surgery for diverticulitis, accounting for death and elective colectomy as competing events.
  
  
  RESULTS
  A total of 14,124 patients were followed for a median of 3.9 years (maximum 10, interquartile range: 1.7-6.4). Five-year cumulative incidence was 9.0% for readmission, 1.9% for emergency surgery, and 14.1% for all-cause mortality. Patients younger than 50 years had higher incidence of readmission than patients aged 50 years and older (10.5% vs 8.4%; P < 0.001) but not emergency surgery (1.8% vs 2.0%; P = 0.52). Patients with complicated disease (abscess, perforation) were at increased risk of readmission than those with uncomplicated disease (12.0% vs 8.2%; P < 0.001), as well as increased risk of emergency surgery (4.3% vs 1.4%, P < 0.001). In multivariable regression, complicated disease and number of prior admissions were associated with increased risk of emergency surgery, yet age less than 50 years was not. Risks associated with complicated disease were nonproportional over time, being highest immediately after discharge and decreasing thereafter.
  
  
  CONCLUSIONS
  Absolute risks of readmission and emergency surgery are low after nonoperative management of diverticulitis, providing evidence for the practice of deferring colectomy for patients without persistent symptoms or multiple recurrences.
authors.affiliation: *Department of Surgery, University of Toronto, Toronto, Ontario, Canada †Department of Surgery and Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada ‡Department of Surgery, Institute of Health Policy, Management and Evaluation, Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada §Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada ¶Department of Surgery, Mount Sinai Hospital, Toronto, Ontario, Canada ‖Department of Family and Community Medicine, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; and **Department of Surgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Debbie
authors.initials: D
authors.lastname: Li
authors.forename: Charles
authors.initials: C
authors.lastname: de Mestral
authors.forename: Nancy N
authors.initials: NN
authors.lastname: Baxter
authors.forename: Robin S
authors.initials: RS
authors.lastname: McLeod
authors.forename: Rahim
authors.initials: R
authors.lastname: Moineddin
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Wilton
authors.forename: Avery B
authors.initials: AB
authors.lastname: Nathens
mesh_terms: D000368:Aged; D003082:Colectomy; D004239:Diverticulitis, Colonic / Q000601:surgery / Q000628:therapy*; D017558:Elective Surgical Procedures; D004632:Emergency Medical Services; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010359:Patient Readmission / Q000706:statistics & numerical data*; D018570:Risk Assessment