title: Illness perceptions and treatment perceptions of patients with chronic kidney disease: different phases, different perceptions?
abstract: OBJECTIVE
  To examine the variability of illness and treatment perceptions - that have been found to be associated with chronic kidney disease (CKD) patients' outcomes (e.g., quality of life) - across the CKD trajectory, by investigating whether there are differences in perceptions in patients: (1) on varying treatments (pre-dialysis, haemodialysis, peritoneal dialysis), (2) with varying lengths of time on (dialysis) treatment, and (3) over time on dialysis, with an 8-month interval.
  
  
  METHODS
  Mixed cross-sectional and longitudinal design, using self-report questionnaires on illness and treatment perceptions; the study sample consisted of 105 pre-dialysis and 161 dialysis patients; of the 161 dialysis patients, 87 patients filled in the questionnaires again after an 8-month interval. Data were examined using multilevel (multivariate) repeated measurements regression analyses, controlled for background characteristics and repeated measures.
  
  
  RESULTS
  Patients on haemodialysis and peritoneal dialysis believed more strongly that their treatment controls their illness (p < .05, p < .01, respectively) and perceived more illness consequences (p < .001, p < .05, respectively) than pre-dialysis patients. Haemodialysis patients perceived more treatment consequences than pre-dialysis (p < .001) and peritoneal dialysis patients (p < .01). The perception of illness understanding fluctuated between patients with varying lengths of time on dialysis (p < .05). Perceived treatment consequences were more negative in patients who were on dialysis for longer lengths of time (p < .01). Lastly, perceptions of illness and treatment varied within dialysis patients over an 8-month interval, with treatment control and personal control showing the lowest correlations.
  
  
  CONCLUSIONS
  Findings suggest that illness and treatment perceptions vary across the CKD trajectory. This indicates that perceptions are amenable to influences and that interventions might potentially be helpful in influencing them in order to improve outcomes.
  What is already known on this subject? Dialysis patients' perceptions of illness understanding and illness symptoms vary over the first year on dialysis. Established haemodialysis patients' perceptions of illness understanding, emotional response and treatment control vary over a 2-year period. Certain illness perceptions as well as treatment perceptions vary as a function of treatment type in patients with CKD stage 5 (dialysis patients, patients with a kidney transplant). What does this study add? Patients' perceptions of illness understanding and treatment consequences vary between patients as a function of length of time on (haemo-, peritoneal-) dialysis, taking into account a wide range of time (0-10 years). Illness perceptions and treatment perceptions of patients on haemodialysis and peritoneal dialysis vary within patients over an 8-month interval, with perceptions of treatment control and personal control showing the highest variations. Perceptions of illness consequences, treatment consequences and treatment control vary as a function of type of treatment, taking into account pre-dialysis treatment (CKD stage 4) and dialysis (haemodialysis, peritoneal dialysis) treatment (CKD stage 5).
authors.affiliation: NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands. d.jansen@nivel.nl
authors.forename: Daphne L
authors.initials: DL
authors.lastname: Jansen
authors.forename: Monique J W M
authors.initials: MJ
authors.lastname: Heijmans
authors.forename: Mieke
authors.initials: M
authors.lastname: Rijken
authors.forename: Peter
authors.initials: P
authors.lastname: Spreeuwenberg
authors.forename: Diana C
authors.initials: DC
authors.lastname: Grootendorst
authors.forename: Friedo W
authors.initials: FW
authors.lastname: Dekker
authors.forename: Elisabeth W
authors.initials: EW
authors.lastname: Boeschoten
authors.forename: Ad A
authors.initials: AA
authors.lastname: Kaptein
authors.forename: Peter P
authors.initials: PP
authors.lastname: Groenewegen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001294:Attitude to Health; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000523:psychology / Q000628:therapy; D016030:Kidney Transplantation / Q000523:psychology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010530:Peritoneal Dialysis / Q000523:psychology; D011446:Prospective Studies; D006435:Renal Dialysis / Q000523:psychology; D051436:Renal Insufficiency, Chronic / Q000523:psychology* / Q000628:therapy; D017582:Renal Replacement Therapy / Q000523:psychology*; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult