title: Factors associated with non-response in proton pump inhibitor users: a study of lansoprazole therapy.
abstract: BACKGROUND
  Proton pump inhibitors (PPI) demonstrate high healing rates of 85-98% in clinical trials. Due to the limited knowledge regarding response and non-response to lansoprazole in daily practice and for the reason that resistance to PPIs is scarce, we investigated factors possibly associated with non-response.
  
  
  METHODS
  Data were used from a prospective, open label, observational follow-up study in which 10,008 lansoprazole users were followed over time. The study was designed according to the SAMM guidelines. A matched nested case-control design was used to compare non-responding (cases) and responding (controls) lansoprazole users. Non-response was defined as worsening or non-improvement of symptoms at the first evaluation after at least 8 weeks of use, response as disappearance or improvement of symptoms within 8 weeks of use. Controls were matched for the evaluating physician.
  
  
  RESULTS
  A total of 186 non-responders and 372 responders to PPI treatment were identified as cases and controls. Age of over 60 years, heavy smoking and previous use of PPIs were significantly more common in non-responding patients compared with responding patients. There were no differences found between the reported diagnosis regarding response.
  
  
  CONCLUSIONS
  In daily clinical practice, previous use of PPIs, heavy smoking and an age > 60 years were significantly associated with non-response to treatment with lansoprazole. Previous use of PPIs in non-responding patients might suggest resistance to PPIs. The knowledge that non-response drives non-response may encourage physicians to follow PPI users with previous PPI use more closely.
authors.affiliation: Department of Pharmacoepidemiology and Pharmacotherapy, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht, The Netherlands.
authors.forename: A A
authors.initials: AA
authors.lastname: Claessens
authors.forename: E R
authors.initials: ER
authors.lastname: Heerdink
authors.forename: C B
authors.initials: CB
authors.lastname: Lamers
authors.forename: J T
authors.initials: JT
authors.lastname: van Eijk
authors.forename: H G
authors.initials: HG
authors.lastname: Leufkens
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D064747:Lansoprazole; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D010349:Patient Compliance / Q000706:statistics & numerical data; D011446:Prospective Studies; D054328:Proton Pump Inhibitors
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D004791:Enzyme Inhibitors; D054328:Proton Pump Inhibitors; D064747:Lansoprazole; D009853:Omeprazole