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

ObjectiveTo 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).MethodsA 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.ResultsCronbach'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 ConclusionsThe 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.