title: Testing for celiac sprue in irritable bowel syndrome with predominant diarrhea: a cost-effectiveness analysis.
abstract: OBJECTIVE
  Some patients with diarrhea-predominant irritable bowel syndrome (IBS-D) may have undiagnosed celiac sprue (CS). Because the symptoms of CS respond to a gluten-free diet, testing for CS in IBS may prevent years of morbidity and attendant expense. We sought to determine whether this might be a cost-effective diagnostic strategy in IBS-D.
  
  
  METHODS
  We used decision analysis to calculate the cost-effectiveness of 2 competing strategies in IBS-D: (1) start empirical IBS treatment and (2) perform serologic test for CS followed by endoscopic biopsy for positive tests. The base-case cohort had a CS prevalence of 3.4%, which was varied between 0% and 100% in sensitivity analysis. The outcome measure was cost per symptomatic improvement.
  
  
  RESULTS
  Under base-case conditions, testing for CS instead of starting empiric IBS therapy cost an incremental $11,000 to achieve one additional symptomatic improvement. Testing for CS became the dominant strategy when the prevalence of CS exceeded 8%, the specificity of CS testing exceeded 98%, or the cost of IBS therapy exceeded $130/month. The incremental cost-effectiveness of testing for CS exceeded $50,000 when the prevalence fell below 1%.
  
  
  CONCLUSIONS
  Testing for CS in patients with IBS-D has an acceptable cost when the prevalence of CS is above 1% and is the dominant strategy when the prevalence exceeds 8%. The decision to test should be based on a consideration of the population prevalence of underlying CS, the operating characteristics of the screening test employed, and the cost of proposed therapy for IBS.
authors.affiliation: Division of Gastroenterology and Hepatology, VA Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Building 115, Room 215B, Los Angeles, CA 90073, USA. bspiegel@ucla.edu
authors.forename: Brennan M R
authors.initials: BM
authors.lastname: Spiegel
authors.forename: Vincent P
authors.initials: VP
authors.lastname: DeRosa
authors.forename: Ian M
authors.initials: IM
authors.lastname: Gralnek
authors.forename: Victor
authors.initials: V
authors.lastname: Wang
authors.forename: Gareth S
authors.initials: GS
authors.lastname: Dulai
mesh_terms: D002446:Celiac Disease / Q000175:diagnosis* / Q000191:economics* / Q000453:epidemiology / Q000517:prevention & control; D003362:Cost-Benefit Analysis; D003967:Diarrhea / Q000175:diagnosis / Q000191:economics; D004032:Diet; D005983:Glutens; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000175:diagnosis* / Q000191:economics* / Q000453:epidemiology / Q000517:prevention & control; D008403:Mass Screening / Q000191:economics*; D015995:Prevalence; D012680:Sensitivity and Specificity
chemical_list: D005983:Glutens