title: Published diagnostic models safely excluded colorectal cancer in an independent primary care validation study.
abstract: OBJECTIVE
  To validate published diagnostic models for their ability to safely reduce unnecessary endoscopy referrals in primary care patients suspected of significant colorectal disease.
  
  
  METHODS
  Following a systematic literature search, we independently validated the identified diagnostic models in a cross-sectional study of 810 Dutch primary care patients with persistent lower abdominal complaints referred for endoscopy. We estimated diagnostic accuracy measures for colorectal cancer (N = 37) and significant colorectal disease (N = 141; including colorectal cancer, inflammatory bowel disease, diverticulitis, or >1-cm adenomas).
  
  
  RESULTS
  We evaluated 18 models-12 specific for colorectal cancer-, of which most were able to safely rule out colorectal cancer: the best model (National Institute for Health and Care Excellence-1) prevented 59% of referrals (95% confidence interval [CI]: 56-63%), with 96% sensitivity (95% CI: 83-100%), 100% negative predictive value (NPV; 95% CI: 99-100%), and an area under the receiver operating characteristics curve (AUC) of 0.86 (95% CI: 0.80-0.92). The models performed less for significant colorectal disease: the best model (Brazer) prevented 23% of referrals (95% CI: 20-26%), with 95% sensitivity (95% CI: 90-98%), 96% NPV (95% CI: 92-98%), and an AUC of 0.73 (95% CI: 0.69-0.78).
  
  
  CONCLUSIONS
  Most models safely excluded colorectal cancer in many primary care patients with lower gastrointestinal complaints referred for endoscopy. Models performed less well for significant colorectal disease.
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, PO Box 85500, Utrecht, GA 3508, The Netherlands. Electronic address: s.elias@umcutrecht.nl.
authors.forename: Sjoerd G
authors.initials: SG
authors.lastname: Elias
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, PO Box 85500, Utrecht, GA 3508, The Netherlands.
authors.forename: Liselotte
authors.initials: L
authors.lastname: Kok
authors.affiliation: Department of Gastroenterology, Gelderse Vallei Hospital, PO Box 9025, Ede, HN 6710, The Netherlands.
authors.forename: Ben J M
authors.initials: BJM
authors.lastname: Witteman
authors.affiliation: Department of Gastroenterology, Atrium Medical Center, PO Box 4446, Heerlen, CX 6401, The Netherlands.
authors.forename: Jelle G
authors.initials: JG
authors.lastname: Goedhard
authors.affiliation: Department of Gastroenterology, Orbis Medical Center, PO Box 5500, Sittard-Geleen, MB 6130, The Netherlands.
authors.forename: Mariëlle J L
authors.initials: MJL
authors.lastname: Romberg-Camps
authors.affiliation: Department of General Practice, Care and Public Health Research Institute (Caphri), Maastricht University, PO Box 616, Maastricht, MD 6200, The Netherlands.
authors.forename: Jean W M
authors.initials: JWM
authors.lastname: Muris
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, PO Box 85500, Utrecht, GA 3508, The Netherlands.
authors.forename: Niek J
authors.initials: NJ
authors.lastname: de Wit
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, PO Box 85500, Utrecht, GA 3508, The Netherlands.
authors.forename: Karel G M
authors.initials: KGM
authors.lastname: Moons
mesh_terms: D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands; D011237:Predictive Value of Tests; D011320:Primary Health Care / Q000379:methods* / Q000706:statistics & numerical data; D012372:ROC Curve; D012017:Referral and Consultation / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity
keywords: Colorectal cancer; Diagnosis; Primary care; Significant colorectal disease; Systematic review; Validation