title: Adherence to phosphate binders in hemodialysis patients: prevalence and determinants.
abstract: BACKGROUND
  Phosphate control is a crucial treatment goal in end-stage renal disease, but poor patient adherence to phosphate binder therapy remains a challenge. This study aimed to estimate the extent of phosphate binder adherence in hemodialysis patients and to identify potential determinants.
  
  
  METHODS
  Phosphate binder adherence was measured blindly in 135 hemodialysis patients for 2 months using the medication event monitoring system. Patient data, gathered at inclusion through medical records, ad hoc questionnaires and the short form (SF)-36 health survey, included: (1) demographics, (2) perceived side-effects, belief in benefit, self-reported adherence to the therapy, (3) knowledge about phosphate binder therapy, (4) social support, and (5) quality of life (SF-36). Phosphatemia data was collected from charts. 'Being adherent' was defined as missing <1 total daily dose/week and 'being totally adherent' as missing <1 total daily dose/week, every week.
  
  
  RESULTS
  Mean age of patients was 67 years and 64 % of the sample was male. Over the 2 months, 78 % of the prescribed doses were taken. Every week, about half of patients were adherent. Over the entire 8-week period, 22 % of patients were totally adherent. Mean phosphatemia levels were 0.55 mg/dl lower in adherent than nonadherent patients (4.76 vs. 5.31 mg/dl). Determinants for being totally adherent were living with a partner, higher social support (both were interrelated) and higher physical quality of life. Experiencing intake-related inconvenience negatively affected adherence. The social support and quality of life physical score explained 26 % of the variance in adherence.
  
  
  CONCLUSIONS
  Phosphate binder nonadherence remains a major problem. Interventions should aim, at least, to improve social support. With few associated factors found and yet low adherence, an individualized approach seems indicated.
authors.affiliation: Faculty of Medicine and Health Sciences, Centre for Research and Innovation in Care (CRIC), Universiteit Antwerpen, CDE R334, Universiteitsplein 1, 2610, Wilrijk, Belgium. yoleen@gmail.com.
authors.forename: Yoleen P M
authors.initials: YP
authors.lastname: Van Camp
authors.affiliation: Department of Biostatistics and Medical Informatics, Université de Liège, Liège, Belgium.|MWV Healthcare, Visé, Belgium.
authors.forename: Bernard
authors.initials: B
authors.lastname: Vrijens
authors.affiliation: Center for Health Outcomes and Pharmacoeconomic Research (HOPE), University of Arizona, Tucson, AZ, USA.
authors.forename: Ivo
authors.initials: I
authors.lastname: Abraham
authors.affiliation: Faculty of Medicine and Health Sciences, Centre for Research and Innovation in Care (CRIC), Universiteit Antwerpen, CDE R334, Universiteitsplein 1, 2610, Wilrijk, Belgium.|Department of Healthcare, Artesis University College of Antwerp, Antwerp, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Van Rompaey
authors.affiliation: Faculty of Medicine and Health Sciences, Centre for Research and Innovation in Care (CRIC), Universiteit Antwerpen, CDE R334, Universiteitsplein 1, 2610, Wilrijk, Belgium.
authors.forename: Monique M
authors.initials: MM
authors.lastname: Elseviers
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D001530:Belgium; D002614:Chelating Agents / Q000009:adverse effects / Q000627:therapeutic use; D054559:Hyperphosphatemia / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D007676:Kidney Failure, Chronic / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D010349:Patient Compliance; D010710:Phosphates / Q000097:blood; D011788:Quality of Life; D006435:Renal Dialysis / Q000009:adverse effects; D012944:Social Support; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D002614:Chelating Agents; D010710:Phosphates
keywords: Adherence; Dialysis; Electronic measurement; Medication; Phosphate binders; Phosphatemia