title: The Bt-DUX: development of a subjective measure of health-related quality of life in patients who underwent surgery for lower extremity malignant bone tumor.
abstract: BACKGROUND
  To examine the practical applicability, internal consistency, and validity of the Bt-DUX, a disease-specific Health Related Quality of Life (HRQoL) instrument. The Bt-Dux was developed to examine patients' individual values of their life after a malignant bone tumor of the lower extremity at four domains (cosmetic, social, emotional, and functional).
  
  
  METHODS
  Patients were eligible for this cross-sectional, multicenter study if they underwent surgery for a malignant tumor of the leg in a period ranging between 12 and 60 months before the recruitment. Assessments included: Bt-DUX, Toronto Extremity Salvage Score (TESS) Short Form (SF)-36, TNO-AZL Questionnaire for Adult's Quality of Life (TAAQOL), and TNO-AZL Children's Quality of Life Questionnaire (TACQOL).
  
  
  RESULTS
  Seventy-two patients (35 male, 37 female), mean age 17 (SD 4) years were included. Limb sparing surgery took place in 32 patients and ablative surgery in 40 patients. The Bt-DUX was completed in less than 5 min and easy to comprehend. The mean Bt-DUX score was 69.8 (SD 15.5), with Cronbach's alpha being 0.92. Domain-total correlations ranged between 0.84 and 0.88 (P < 0.01). Correlations between Bt-DUX Total score and TESS, SF-36 Physical and Mental Component Summary scales and selected TACQOL and TAAQOL scores were statistically significant (P < 0.05), except for the social scale of the TACQOL. The Bt-DUX was able to discriminate between patients with higher and lower TESS scores (P < 0.05).
  
  
  CONCLUSIONS
  The Bt-DUX was found to be a practical and valid instrument. Its added value compared with existing HRQoL measures needs to be further established.
authors.affiliation: Department of Physical Therapy, Leiden University Medical Center, Leiden, The Netherlands. w.p.bekkering@lumc.nl
authors.forename: W Peter
authors.initials: WP
authors.lastname: Bekkering
authors.forename: Theodora P M Vliet
authors.initials: TP
authors.lastname: Vlieland
authors.forename: Hendrik M
authors.initials: HM
authors.lastname: Koopman
authors.forename: Gerard R
authors.initials: GR
authors.lastname: Schaap
authors.forename: H W Bart
authors.initials: HW
authors.lastname: Schreuder
authors.forename: Auke
authors.initials: A
authors.lastname: Beishuizen
authors.forename: Wim J E
authors.initials: WJ
authors.lastname: Tissing
authors.forename: Peter M
authors.initials: PM
authors.lastname: Hoogerbrugge
authors.forename: Jacob K
authors.initials: JK
authors.lastname: Anninga
authors.forename: Antonie H M
authors.initials: AH
authors.lastname: Taminiau
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000503:physiopathology / Q000523:psychology* / Q000601:surgery; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006801:Humans; D007866:Leg; D008297:Male; D011788:Quality of Life; D055815:Young Adult