title: Nonadherence with immunosuppressive drugs: U.S. compared with European kidney transplant recipients.
abstract: BACKGROUND
  System factors increasingly are suggested as important yet understudied correlates of nonadherence.
  
  
  OBJECTIVE
  To explore the relationship between healthcare system and prevalence of nonadherence with immunosuppressive regimen by studying variation in nonadherence between European and US kidney transplant recipients and as well as nonadherence in European countries.
  
  
  METHODS
  We performed a secondary data analysis on data collected in 3 independent cross-sectional studies using comparable methodology including patients from the United States, the Netherlands, Belgium, and Switzerland. Nonadherence was measured using 1 item of the Siegal questionnaire. Patients were categorized as nonadherent if they reported missing a dose of immunosuppression in the last 4 weeks. Analyses were performed by multiple mixed logistic regression, with center as a random effect and clinical and demographical differences between groups as fixed effects.
  
  
  RESULTS
  1563 U.S. and 614 European patients from 3 different countries (Belgium [n=187], the Netherlands [n=85], and Switzerland [n=342]) were included. Prevalence of nonadherence in the United States and Europe was 19.3% and 13.2.%, respectively. This higher nonadherence in US patients was confirmed in a multiple logistic regression analysis (OR = 1.78; 95% CI, 1.10-2.89). Nonadherence differed between Belgium (16%) and the Netherlands (14.1%) (OR = 0.27; 95% CI, 0.09-0.80) and between Belgium and Switzerland (11.4%; OR = 0.17; 95% CI, 0.0-0.42).
  
  
  CONCLUSIONS
  This is the first study showing differences in prevalence of nonadherence between European and US patients and among European patients. Further research should aim at unraveling the dynamics explaining these differences.
authors.affiliation: University of Basel, Switzerland.
authors.forename: Kris
authors.initials: K
authors.lastname: Denhaerynck
authors.forename: Ariane
authors.initials: A
authors.lastname: Desmyttere
authors.forename: Fabienne
authors.initials: F
authors.lastname: Dobbels
authors.forename: Philip
authors.initials: P
authors.lastname: Moons
authors.forename: Jim
authors.initials: J
authors.lastname: Young
authors.forename: Bonita
authors.initials: B
authors.lastname: Siegal
authors.forename: Stuart
authors.initials: S
authors.lastname: Greenstein
authors.forename: Jürg
authors.initials: J
authors.lastname: Steiger
authors.forename: Yves
authors.initials: Y
authors.lastname: Vanrenterghem
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Squifflet
authors.forename: Johannes P
authors.initials: JP
authors.lastname: van Hooff
authors.forename: Sabina
authors.initials: S
authors.lastname: De Geest
mesh_terms: D000328:Adult; D000368:Aged; D001530:Belgium; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D003695:Delivery of Health Care / Q000458:organization & administration; D004522:Educational Status; D005260:Female; D019538:Health Care Surveys; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D016030:Kidney Transplantation / Q000208:ethnology / Q000276:immunology / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009426:Netherlands; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013557:Switzerland; D013597:Systems Analysis; D016312:Treatment Refusal / Q000208:ethnology / Q000706:statistics & numerical data*; D014481:United States
chemical_list: D007166:Immunosuppressive Agents