title: Use of thiopurine testing in the management of inflammatory bowel diseases in clinical practice: a worldwide survey of experts.
abstract: BACKGROUND
  We performed a worldwide survey to evaluate the extent to which gastroenterologists who are experts in the field of inflammatory bowel diseases (IBDs) are utilizing thiopurine metabolism in practice.
  
  
  METHODS
  This was a Web-based cross-sectional survey consisting of 12 multiple-choice and open-ended questions.
  
  
  RESULTS
  Between December 2009 and April 2010, 175 questionnaires were received. The proportion of practitioners with access and reimbursement for thiopurine S-methyltransferase (TPMT) genotype, TPMT phenotype, 6-thioguanine nucleotides (6-TGN) levels, and 6-methylmercaptopurine ribonucleotides (6-MMP) levels was 48%, 54%, 44%, and 35%, respectively. Before azathioprine initiation, TPMT genotype and phenotype were performed by only 30% and 43% of responders, respectively. In patients on thiopurine therapy, 6-TGN and 6-MMP levels were determined by 54% and 44% of responders, respectively. Only 27% of physicians always wait for TMPT activity/genotype results before initiating azathioprine and 81% do not routinely recheck metabolite levels after dose escalation or reduction. In cases of very high or low TPMT activity, 75% and 74% of practitioners take into account TMPT activity result, respectively. If access to all azathioprine metabolite measurements was available and if all these tests were reimbursed by public health insurance, 47% of responders would use these tests more often in their practice. The availability and reimbursement of TPMT status and azathioprine metabolites strongly influenced experts' attitudes.
  
  
  CONCLUSIONS
  Thiopurine testing is relatively underutilized by IBD gastroenterologists. The availability and reimbursement of TPMT status and azathioprine metabolites strongly influence the management of IBD patients treated with thiopurines.
authors.affiliation: Department of Hepato-Gastroenterology, University Hospital of Saint-Etienne, Saint-Etienne, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Roblin
authors.forename: Abderrahim
authors.initials: A
authors.lastname: Oussalah
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Chevaux
authors.forename: Miles
authors.initials: M
authors.lastname: Sparrow
authors.forename: Laurent
authors.initials: L
authors.lastname: Peyrin-Biroulet
mesh_terms: D001379:Azathioprine / Q000008:administration & dosage*; D015415:Biomarkers / Q000032:analysis; D003430:Cross-Sectional Studies; D005762:Gastroenterology; D005820:Genetic Testing; D005838:Genotype; D014943:Global Health; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics; D015122:Mercaptopurine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008780:Methyltransferases / Q000235:genetics*; D010641:Phenotype; D010818:Practice Patterns, Physicians'; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; C010240:6-methylthiopurine; D015122:Mercaptopurine; D008780:Methyltransferases; C022745:thiopurine methyltransferase; D001379:Azathioprine