title: The influence of time and adaptation on health state valuations in patients with spinal cord injury.
abstract: One of the explanations for the difference between health state utilities elicited from patients and the public--often provided but seldom studied--is adaptation. The influence of adaptation on utilities was investigated in patients with spinal cord injury.
  
  
  
  Interviews were held at 3 time points (T1, after admission to the rehabilitation center; T2, during active rehabilitation; T3, at least half a year after discharge). At T1, 60 patients were interviewed; 10 patients withdrew at T2 and T3. At all time points, patients were asked to value their own health and a health state description of rheumatoid arthritis on a time trade-off and a visual analogue scale. The Barthel Index, a measure of independence from help in activities of daily living, and the adjustment ladder were filled out. Main analyses were performed using mixed linear models taking the time-dependent covariates (Barthel Index and adjustment ladder) into account.
  
  
  
  Time trade-off valuations for patients' own health changed over time, even after correction for gain in independence from help in activities of daily living, F(2, 59) = 8.86, P < 0.001. This change was related to overall adaptation. Both a main effect for adaptation, F(87, 1) = 10.05; P = 0.002, and an interaction effect between adaptation and time, F(41, 1)= 4.10, P = 0.024, were seen for time trade-off valuations. Valuations given for one's own health on the visual analogue scale did not significantly change over time, nor did the valuations for the hypothetical health state.
  
  
  
  Patients' health state valuations change over time, over and above the change expected by the rehabilitation process, and this change is partly explained by adaptation. Experience with a chronic illness did not lead to change in valuations of hypothetical health states.
authors.affiliation: Leiden University Medical Center, Department of Medical Decision Making, Leiden, The Netherlands (YP, AMS)
authors.forename: Yvette
authors.initials: Y
authors.lastname: Edelaar-Peeters
authors.affiliation: Leiden University Medical Center, Department of Medical Statistics and Bioinformatics, Leiden, The Netherlands (HP)
authors.forename: Hein
authors.initials: H
authors.lastname: Putter
authors.affiliation: Rehabilitation Center Het Roessingh and Roessingh Research and Development, Enschede, The Netherlands (GJS)
authors.forename: Govert J
authors.initials: GJ
authors.lastname: Snoek
authors.affiliation: Rijndam Rehabilitation Center Rotterdam, The Netherlands (TARS)
authors.forename: Tebbe A R
authors.initials: TA
authors.lastname: Sluis
authors.affiliation: Reade, Centre for Rehabilitation and Rheumatology, Amsterdam, The Netherlands (CAJS)
authors.forename: Christof A J
authors.initials: CA
authors.lastname: Smit
authors.affiliation: Rudolf Magnus Institute of Neuroscience and Center of Excellence in Rehabilitation Medicine, University Medical Center, Utrecht, and De Hoogstraat, Utrecht, The Netherlands (MWMP)
authors.forename: Marcel W M
authors.initials: MW
authors.lastname: Post
authors.affiliation: Leiden University Medical Center, Department of Medical Decision Making, Leiden, The Netherlands (YP, AMS)
authors.forename: Anne M
authors.initials: AM
authors.lastname: Stiggelbout
mesh_terms: D000222:Adaptation, Physiological; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands; D013119:Spinal Cord Injuries / Q000208:ethnology / Q000503:physiopathology*; D013996:Time and Motion Studies