title: Psychometrics of the Short Form 36 Health Survey version 2 (SF-36v2) and the Quality of Life Scale for Drug Addicts (QOL-DAv2.0) in Chinese mainland patients with methadone maintenance treatment.
abstract: OBJECTIVE
  To test psychometrics of the Short Form 36 Health Survey version 2 (SF-36v2) and the Quality of Life Scale for Drug Addicts (QOL-DAv2.0) in Chinese mainland patients with methadone maintenance treatment (MMT).
  
  
  METHODS
  A total of 1,212 patients were recruited from two MMT clinics in Xi'an, China. Reliability was estimated with Cronbach's α and intra-class correlation (ICC). Convergent and discriminant validity was assessed using multitrait-multimethod correlation matrix. Sensitivity was measured with ANOVA and relative efficiency. Responsiveness was evaluated by pre-post paired-samples t-test and standardized response mean based on the patients' health status changes following 6-month period.
  
  
  RESULTS
  Cronbach's α of the SF-36v2 physical and mental summary components were 0.80 and 0.86 (eight scales range 0.73-0.92) and the QOL-DAv2.0 was 0.96 (four scales range: 0.80-0.93). ICC of the SF-36v2 two components were 0.86 and 0.85 (eight scales range: 0.72-0.87) and the QOL-DAv2.0 was 0.94 (four scales range: 0.88-0.92). Convergent validity was lower between the two instruments (γ <0.70) while discriminant validity was acceptable within each instrument. Sensitivity was satisfied in self-evaluated health status (both instruments) and average daily methadone dose (SF-36v2 physical functioning and vitality scales; QOL-DAv2.0 except psychology scale). Responsiveness was acceptable in the improved health status change (SF-36v2 except vitality scale; QOL-DAv2.0 except psychology and symptoms scales) and deteriorated health status change (SF-36v2 except vitality, social functioning and mental health scales; QOL-DAv2.0 except society scale).
  
  
  CONCLUSIONS
  The SF-36v2 and the QOL-DAv2.0 are valid tools and can be used independently or complementary according to different emphases of health-related quality of life evaluation in patients with MMT.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.
authors.forename: Kaina
authors.initials: K
authors.lastname: Zhou
authors.forename: Guihua
authors.initials: G
authors.lastname: Zhuang
authors.forename: Hongmei
authors.initials: H
authors.lastname: Zhang
authors.forename: Peifeng
authors.initials: P
authors.lastname: Liang
authors.forename: Juan
authors.initials: J
authors.lastname: Yin
authors.forename: Lingling
authors.initials: L
authors.lastname: Kou
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Hao
authors.forename: Lijuan
authors.initials: L
authors.lastname: You
mesh_terms: D000328:Adult; D002681:China; D055030:Drug Users; D005260:Female; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use*; D008875:Middle Aged; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life
chemical_list: D008691:Methadone