title: Social network analysis of duplicative prescriptions: One-month analysis of medical facilities in Japan.
abstract: OBJECTIVE
  Duplicative prescriptions refer to situations in which patients receive medications for the same condition from two or more sources. Health officials in Japan have expressed concern about medical "waste" resulting from this practices. We sought to conduct descriptive analysis of duplicative prescriptions using social network analysis and to report their prevalence across ages.
  
  
  METHODS
  We analyzed a health insurance claims database including 1.24 million people from December 2012. Through social network analysis, we examined the duplicative prescription networks, representing each medical facility as nodes, and individual prescriptions for patients as edges.
  
  
  RESULTS
  The prevalence of duplicative prescription for any drug class was strongly correlated with its frequency of prescription (r=0.90). Among patients aged 0-19, cough and colds drugs showed the highest prevalence of duplicative prescriptions (10.8%). Among people aged 65 and over, antihypertensive drugs had the highest frequency of prescriptions, but the prevalence of duplicative prescriptions was low (0.2-0.3%). Social network analysis revealed clusters of facilities connected via duplicative prescriptions, e.g., psychotropic drugs showed clustering due to a few patients receiving drugs from 10 or more facilities.
  
  
  CONCLUSIONS
  Overall, the prevalence of duplicative prescriptions was quite low - less than 10% - although the extent of the problem varied by drug class and age group. Our approach illustrates the potential utility of using a social network approach to understand these practices.
authors.affiliation: Department of Health Informatics, Kyoto University School of Public Health, Yoshida-Konoe, Sakyo, Kyoto 606-8501, Japan; Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Boston, MA 02115, USA. Electronic address: y-takahashi@umin.ac.jp.
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Research Team for Human Care, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae, Itabashi, Tokyo 173-0015, Japan. Electronic address: tatsuro@tmig.or.jp.
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Ishizaki
authors.affiliation: Department of Health Informatics, Kyoto University School of Public Health, Yoshida-Konoe, Sakyo, Kyoto 606-8501, Japan. Electronic address: nakayama.takeo.4a@kyoto-u.ac.jp.
authors.forename: Takeo
authors.initials: T
authors.lastname: Nakayama
authors.affiliation: Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Boston, MA 02115, USA. Electronic address: ikawachi@hsph.harvard.edu.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawachi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D005260:Female; D006300:Health Services Misuse / Q000706:statistics & numerical data*; D006801:Humans; D007348:Insurance, Health / Q000706:statistics & numerical data; D007564:Japan; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012944:Social Support; D055815:Young Adult
keywords: Duplicative prescription; Health policy; Health service research; Prescription drugs; Social networks