title: Determinants of initiation and suboptimal use of anti-ulcer medication: a study of the Quebec older population.
abstract: OBJECTIVE
  To describe the use of anti-ulcer medication in the Quebec older population; to examine determinants of initiation, suboptimal use, and switches between products.
  
  
  METHODS
  Population-based retrospective cohort study.
  
  
  METHODS
  Universal health program for older adults in Quebec.
  
  
  METHODS
  5000 users and 5000 non-users of anti-ulcer medications were selected randomly. Use was defined as the presence in the 1991 prescription database of an anti-ulcer prescription. Among users, 1697 (34%) were new users and were considered as the exposure group. Subjects were followed for 365 days after inclusion.
  
  
  METHODS
  Measured were patient's age, gender, prescribed duration of anti-ulcer medication, concomitant medications, and gastrointestinal diagnostic procedures.
  
  
  RESULTS
  A total of 17% of new users had unusually short courses; 18% were long-term users. There was no difference in duration for omeprazole compared with other anti-ulcer medications. First-time use of NSAIDs was the strongest predictor of initiation of anti-ulcer medication (odds ratio = 3.21; 95% CI, 2.66-3.88). Twenty-six percent of users switched brands. Only 9.5% of new users underwent a diagnostic procedure before initiation of therapy, and 49% of long-term users ever underwent such procedure.
  
  
  CONCLUSIONS
  Despite a relatively homogeneous recommended duration of therapy, patterns of use of anti-ulcer medication among older people are highly variable, and treatment is often not accompanied by a diagnostic procedure.
authors.affiliation: Centre for Clinical Epidemiology and Community Studies, McGill University S.M.B.D. Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Moride
authors.forename: D
authors.initials: D
authors.lastname: Melnychuk
authors.forename: J
authors.initials: J
authors.lastname: Monette
authors.forename: L
authors.initials: L
authors.lastname: Abenhaim
mesh_terms: D000367:Age Factors; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D004363:Drug Utilization; D006801:Humans; D011792:Quebec; D012189:Retrospective Studies
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000897:Anti-Ulcer Agents