title: Determinants of self-reported medicine underuse due to cost: a comparison of seven countries.
abstract: OBJECTIVE
  To compare the predictors of self-reported medicine underuse due to cost across countries with different pharmaceutical subsidy systems and co-payments.
  
  
  METHODS
  We analysed data from a 2007 survey of adults in Australia, Canada, Germany, the Netherlands, New Zealand (NZ), the United Kingdom (UK) and the United States (US). The predictors of underuse were calculated separately for each country using multivariate poisson regression.
  
  
  RESULTS
  Reports of underuse due to cost varied from 3% in the Netherlands to 20% in the US. In Australia, Canada, NZ, the UK and the US, cost-related underuse was predicted by high out-of-pocket costs (RR range 2.0-4.6), below average income (RR range 1.9-3.1), and younger age (RR range 3.9-16.4). In all countries except Australia and the UK, history of depression was associated with cost-related underuse (RR range 1.2-4.1). In Australia, Canada, Germany, the UK and the US lack of patient involvement in treatment decisions was associated with cost-related underuse (RR range 1.2-1.4). In Australia, Canada and NZ, indigenous persons more commonly reported underuse due to cost (RR range 2.1-2.9).
  
  
  CONCLUSIONS
  Cost-related underuse of medicines was least commonly reported in countries with the lowest out-of-pocket costs, the Netherlands and the UK. Countries with reduced co-payments or cost ceilings for low income patients showed the least disparity in rates of underuse between income groups. Despite differences in health insurance systems in these countries, age, ethnicity, depression, and involvement with treatment decisions were consistently predictive of underuse. There are opportunities for policy makers and clinicians to support medicine use in vulnerable groups.
authors.affiliation: The University of Western Australia, Perth, WA 6009, Australia. anna.kemp@uwa.edu.au
authors.forename: Anna
authors.initials: A
authors.lastname: Kemp
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Roughead
authors.forename: David
authors.initials: D
authors.lastname: Preen
authors.forename: John
authors.initials: J
authors.lastname: Glover
authors.forename: James
authors.initials: J
authors.lastname: Semmens
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019049:Developed Countries; D005260:Female; D005382:Financing, Personal; D019538:Health Care Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D016012:Poisson Distribution; D011306:Prescription Fees; D055815:Young Adult