title: Predictors of self-reported adherence to antihypertensive medicines: a multinational, cross-sectional survey.
abstract: BACKGROUND
  Nonadherence to antihypertensive medicines limits their effectiveness, increases the risk of adverse health outcome, and is associated with significant health care costs. The multiple causes of nonadherence differ both within and between patients and are influenced by patients' care settings.
  
  
  OBJECTIVE
  The objective of this article was to identify determinants of patient nonadherence to antihypertensive medicines, drawing from psychosocial and economic models of behavior.
  
  
  METHODS
  Outpatients with hypertension from Austria, Belgium, England, Germany, Greece, Hungary, The Netherlands, Poland, and Wales were recruited to a cross-sectional online survey. Nonadherence to medicines was assessed using the Morisky Medication Adherence Scale (primary outcome) and the Medication Adherence Rating Scale. Associations with adherence and nonadherence were tested for demographic, clinical, and psychosocial factors.
  
  
  RESULTS
  A total of 2595 patients completed the questionnaire. The percentage of patients classed as nonadherent ranged from 24% in The Netherlands to 70% in Hungary. Low age, low self-efficacy, and respondents' perceptions of their illness and cost-related barriers were associated with nonadherence measured on the Morisky Medication Adherence Scale across several countries. In multilevel, multivariate analysis, low self-efficacy (odds ratio = 0.73; 95% confidence interval 0.70-0.77) and a high number of perceived barriers to taking medicines (odds ratio = 1.70; 95% confidence interval 1.38-2.09) were the main significant determinants of nonadherence. Country differences explained 11% of the variance in nonadherence.
  
  
  CONCLUSIONS
  Among the variables measured, patients' adherence to antihypertensive medicines is influenced primarily by their self-efficacy, illness beliefs, and perceived barriers. These should be targets for interventions for improving adherence, as should an appreciation of differences among the countries in which they are being delivered.
authors.affiliation: School of Psychology, Bangor University, Bangor, UK.
authors.forename: Valerie L
authors.initials: VL
authors.lastname: Morrison
authors.affiliation: Centre for Health Economics & Medicines Evaluation, Bangor University, Bangor, UK.
authors.forename: Emily A F
authors.initials: EA
authors.lastname: Holmes
authors.affiliation: School of Psychology, Bangor University, Bangor, UK.
authors.forename: Sahdia
authors.initials: S
authors.lastname: Parveen
authors.affiliation: Centre for Health Economics & Medicines Evaluation, Bangor University, Bangor, UK.
authors.forename: Catrin O
authors.initials: CO
authors.lastname: Plumpton
authors.affiliation: Keele University, Keele, Staffordshire, UK.
authors.forename: Wendy
authors.initials: W
authors.lastname: Clyne
authors.affiliation: University of Leuven, Leuven, Belgium.
authors.forename: Sabina
authors.initials: S
authors.lastname: De Geest
authors.affiliation: University of Leuven, Leuven, Belgium.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Dobbels
authors.affiliation: MWV Healthcare, Visé, Belgium.
authors.forename: Bernard
authors.initials: B
authors.lastname: Vrijens
authors.affiliation: Medical University of Lodz, Lodz, Poland.
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Kardas
authors.affiliation: Centre for Health Economics & Medicines Evaluation, Bangor University, Bangor, UK. Electronic address: d.a.hughes@bangor.ac.uk.
authors.forename: Dyfrig A
authors.initials: DA
authors.lastname: Hughes
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D003430:Cross-Sectional Studies; D005260:Female; D005544:Forecasting; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000453:epidemiology; D038622:Internationality; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D020377:Self Efficacy; D057566:Self Report / Q000592:standards
chemical_list: D000959:Antihypertensive Agents
keywords: adherence; behavioral economics; health psychology; hypertension; self-efficacy