title: The changing patterns of dispensing branded and generic drugs for the treatment of gastroesophageal reflux disease between 2006 and 2011 in Japan: a retrospective cohort study.
abstract: BACKGROUND
  Despite rising healthcare costs, generic drugs are less frequently dispensed in Japan compared with other developed countries. This study aimed to describe changes in dispensing of branded and generic drugs and to explore possible factors that promote the use of generic drugs.
  
  
  METHODS
  We conducted a retrospective cohort study using a Japanese medical and pharmacy claims database. All proton pump inhibitors (PPIs) and histamine H2-receptor antagonists (H2RAs) with indications for gastroesophageal reflux disease (GERD) described on Japanese labels were included. Patterns of dispensing branded and generic drugs for the treatment of GERD between 2006 and 2011 were analyzed. Multivariate logistic regression was applied to investigate factors associated with receiving generic drugs.
  
  
  RESULTS
  The study cohort included 14,590 patients (male: 50.2%, mean age: 43.1 years). Branded drugs for GERD were still frequently dispensed despite an increase in the share of generic drugs. Only 4.3% of patients who initially received branded drugs switched to generic drugs. The percentage of patients who received only generic drugs increased over time (6.5% to 22.1%). The frequency of generic drug dispensing was the highest in the setting where both prescription and dispensing were implemented in clinics (43.3%), while the lowest in the setting where both prescription and dispensing were implemented in hospitals (11.5%). Factors associated with receiving generic drugs included year of dispensing (adjusted OR 2.22, 95% CI 1.94 to 2.55 for 2009-11 v 2006-8), prescription and dispensing setting (OR 1.81, 95% CI 1.44 to 2.26 for prescription in hospitals and dispensing in community pharmacies; OR 2.21, 95% CI 1.80 to 2.72 for prescription in clinics and dispensing in community pharmacies; and OR 4.55, 95% CI 3.68 to 5.62 for prescription and dispensing in clinics v prescription and dispensing in hospitals) and H2RAs (OR 1.64, 95% CI 1.49 to 1.81 compared to PPIs).
  
  
  CONCLUSIONS
  The share of generic drugs for the treatment of GERD increased over time although branded drugs for GERD were still dispensed frequently. The use of generic drugs for GERD was influenced not only by government policies but also by changes in treatment approach and the setting of prescription and dispensing.
authors.affiliation: Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan. murata.kyoko.5m@kyoto-u.ac.jp.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Murata
authors.affiliation: Center for Innovative Clinical Medicine, Okayama University Hospital, Okayama, Japan. hinotsus@cc.okayama-u.ac.jp.
authors.forename: Shiro
authors.initials: S
authors.lastname: Hinotsu
authors.affiliation: Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan. hamada.shota.4m@kyoto-u.ac.jp.
authors.forename: Shota
authors.initials: S
authors.lastname: Hamada
authors.affiliation: Department of Therapeutic Oncology, Kyoto University Hospital, Kyoto, Japan. yasuzoe@kuhp.kyoto-u.ac.jp.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Ezoe
authors.affiliation: Department of Therapeutic Oncology, Kyoto University Hospital, Kyoto, Japan. mmuto@kuhp.kyoto-u.ac.jp.
authors.forename: Manabu
authors.initials: M
authors.lastname: Muto
authors.affiliation: Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan. kawakami.koji.4e@kyoto-u.ac.jp.
authors.forename: Koji
authors.initials: K
authors.lastname: Kawakami
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D019049:Developed Countries / Q000706:statistics & numerical data; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D057915:Drug Substitution / Q000706:statistics & numerical data*; D016568:Drugs, Generic / Q000627:therapeutic use*; D005260:Female; D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006635:Histamine H2 Antagonists / Q000627:therapeutic use*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D054328:Proton Pump Inhibitors / Q000191:economics / Q000627:therapeutic use*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D016568:Drugs, Generic; D006635:Histamine H2 Antagonists; D054328:Proton Pump Inhibitors