title: Do clinical marker states improve responsiveness and construct validity of the standard gamble and feeling thermometer: a randomized multi-center trial in patients with chronic respiratory disease.
abstract: BACKGROUND
  Optimizing the validity and responsiveness of utility measures will enhance their usefulness in randomized trials. We evaluated the impact of clinical marker state (CMS) rating prior to patients' rating their own health on two utility instruments (feeling thermometer (FT) and standard gamble (SG)) in patients with chronic respiratory disease (CRD).
  
  
  METHODS
  We randomized 182 patients with CRD to complete the FT (self-administered) and SG with CMS (FT+/SG+, n=91) or without marker states (FT-/SG-, n=91) before and after undergoing respiratory rehabilitation in a multi-center trial.
  
  
  RESULTS
  Use of CMS did not influence baseline utility scores. Improvement after therapy on the scale from 0 (dead) to 1.0 (full health) was 0.04 both in FT+ (p=0.03) and FT- (p=0.02; the difference between FT+ and FT- was 0.00, p=0.83). Improvement on the SG was 0.05 in both SG+ (p=0.08) and SG- (p=0.04; difference between SG+ and SG- 0.00, p=0.95). Correlations with other health related quality of life scores were highest for FT+.
  
  
  CONCLUSIONS
  Administration of CMS did not improve responsiveness of the FT but may have improved construct validity. The SG showed limited construct validity and responsiveness that was not influenced by CMS use.
authors.affiliation: Division of Clinical Research Development and INFORMAtion Translation/INFROMA, Italian National Cancer Institute Regina Elena, Rome, Italy. schuneh@mcmaster.ca
authors.forename: Holger J
authors.initials: HJ
authors.lastname: Schünemann
authors.forename: Roger
authors.initials: R
authors.lastname: Goldstein
authors.forename: M Jeffery
authors.initials: MJ
authors.lastname: Mador
authors.forename: Douglas
authors.initials: D
authors.lastname: McKim
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Stahl
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Griffith
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Bayoumi
authors.forename: Peggy
authors.initials: P
authors.lastname: Austin
authors.forename: Gordon H
authors.initials: GH
authors.lastname: Guyatt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001294:Attitude to Health; D015415:Biomarkers; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017060:Patient Satisfaction; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D012120:Respiration Disorders / Q000401:mortality / Q000523:psychology* / Q000534:rehabilitation; D012129:Respiratory Function Tests; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D026712:Value of Life
chemical_list: D015415:Biomarkers