title: Intermittent claudication: symptom severity versus health values.
abstract: OBJECTIVE
  The objective of this study was to obtain health values from patients with intermittent claudication with five different instruments and to study the construct validity of these measures of health-related quality of life by examining their relation with symptom severity.
  
  
  METHODS
  We included all patients with intermittent claudication who participated in an exercise program of the Department of Internal Medicine at our university hospital (n = 92). Health value instruments included the verbal rating scale, time trade-off, standard gamble, EuroQol, and the Health Utilities Index (Mark III). Symptom-free walking distance was used as a measure of symptom severity.
  
  
  RESULTS
  For all instruments the average health values in groups of patients with a symptom-free walking distance < or = 150 m were lower than the average values in patients with a greater walk distance, but the differences for the time trade-off and the standard gamble were small, and only the differences for the verbal rating scale and the EuroQol were statistically significant. At the individual patient level considerable heterogeneity was seen, and the statistical association of the symptom-free walking distance with health values varied from poor to moderate (Spearman rank correlations, 0.03 to 0.48; p values, 0.003 to 0.78).
  
  
  CONCLUSIONS
  At least for the verbal rating scale and the EuroQol, the results of our study provide evidence of the validity of the various health value instruments in a population of patients with peripheral arterial occlusive disease.
authors.affiliation: Department of Health Sciences, University of Groningen, The Netherlands.
authors.forename: S O
authors.initials: SO
authors.lastname: de Vries
authors.forename: W D
authors.initials: WD
authors.lastname: Kuipers
authors.forename: M G
authors.initials: MG
authors.lastname: Hunink
mesh_terms: D000368:Aged; D001294:Attitude to Health; D005080:Exercise Test; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D007383:Intermittent Claudication / Q000145:classification / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires / Q000592:standards*; D013997:Time Factors; D016138:Walking