title: External validation of two tools for the clinical diagnosis of acute diverticulitis without imaging.
abstract: OBJECTIVE
  External validation and comparison of the diagnostic accuracy of two predictive tools, the emergency department triad and the clinical scoring tool in diagnosing acute diverticulitis.
  
  
  METHODS
  Two derivation datasets were used crosswise for external validation. In addition, both tools were validated in a third independent cohort. Predictive values were reassessed and the Area Under the Curve expressed discriminatory capacity. Performance was compared by calculating positive predictive values of the emergency department triad in the validation cohorts and with a cut-off analysis for the clinical scoring tool at a positive predictive value of 90%.
  
  
  RESULTS
  Predictive value of the emergency department triad was comparable to the clinical scoring tool. The positive predictive value of the emergency department triad (97%) decreased in the clinical scoring tool cohort (81%) and was excellent in the independent cohort (100%), identifying 24%, 20% and 14% of the patients. A smaller proportion of patients with diverticulitis could be identified with the clinical scoring tool (6%, 19% and 9%).
  
  
  CONCLUSIONS
  The emergency department triad as well as the clinical scoring tool have significant predictive value in external cohorts of patients suspected of diverticulitis. These tools can be used to select patients in whom additional imaging to diagnose acute diverticulitis may be omitted.
authors.affiliation: Department of Surgery, Academic Medical Centre, Amsterdam, The Netherlands. Electronic address: J.J.Kiewiet@amc.uva.nl.
authors.forename: Jordy J S
authors.initials: JJ
authors.lastname: Kiewiet
authors.affiliation: Department of Surgery, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Andeweg
authors.affiliation: Department of Surgery, Mora Hospital, Mora, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Laurell
authors.affiliation: Department of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Lidewine
authors.initials: L
authors.lastname: Daniels
authors.affiliation: Department of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Wytze
authors.initials: W
authors.lastname: Laméris
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Johannes B
authors.initials: JB
authors.lastname: Reitsma
authors.affiliation: Department of Epidemiology, Biostatistics and HTA, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Jan C M
authors.initials: JC
authors.lastname: Hendriks
authors.affiliation: Department of Surgery, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Bleichrodt
authors.affiliation: Department of Surgery, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: van Goor
authors.affiliation: Department of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Marja A
authors.initials: MA
authors.lastname: Boermeester
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000208:Acute Disease; D000328:Adult; D000367:Age Factors; D000368:Aged; D015331:Cohort Studies; D003661:Decision Support Techniques; D004239:Diverticulitis, Colonic / Q000150:complications / Q000175:diagnosis*; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: Clinical diagnosis; Diverticulitis; External validation; Prediction