TY - JOUR
T1 - Psychometric evaluation, using Rasch analysis, of the WHOQOL-BREF in heroin-dependent people undergoing methadone maintenance treatment
T2 - Further item validation
AU - Chang, Kun Chia
AU - Wang, Jung Der
AU - Tang, Hsin Pei
AU - Cheng, Ching Ming
AU - Lin, Chung Ying
N1 - Funding Information:
This study was supported by grants DOH96-NNB-1032 and DOH98-NNB-1036 from the Taiwan Department of Health. This research was supported in part by (received funding from) the Headquarters of University Advancement at the National Cheng Kung University, which is sponsored by the Ministry of Education, Taiwan, ROC.
Publisher Copyright:
© 2014 Chang et al.; licensee BioMed Central Ltd.
PY - 2014/10/3
Y1 - 2014/10/3
N2 - Background: The brief version of World Health Organization Quality of Life assessment (WHOQOL-BREF), a useful outcome measure for clinical decision making, has been evaluated using classical test theory (CTT) for psychometric properties on heroin-dependent patients. However, CTT has a major disadvantage of invalid summated score, and using Rasch models can overcome the shortcoming. The purpose of this study was using Rasch models to evaluate the psychometric properties of the WHOQOL-BREF for heroin-dependent patients, and the hypothesis was that each WHOQOL-BREF domain is unidimensional.Methods: Two hundred thirty six participants (24 females, mean [SD] age = 38.07 [7.44] years, first used heroin age = 26.13 [6.32] years), with a diagnosis of opioid dependence, were recruited from a methadone maintenance treatment program. Each participant filled out the WHOQOL-BREF. Parallel analysis (PA) and Rasch rating scale models were used for statistical analyses.Results: Based on the PA analyses, four domains of the WHOQOL-BREF were unidimensional. The Rasch analyses showed three negatively worded items (2 in Physical and 1 in Psychological) reported as misfits that may not contribute to the Physical and Psychological domains; one positively worded item in the Physical domain may be redundant. All values for the separation indices were above 2 except for the person separation index in the Physical domain (1.93). Category functioning and item independency of four WHOQOL-BREF domains were supported by the Rasch analyses, and there were 5 items showing the differential item function (DIF) for positive versus negative HIV (human immunodeficiency virus) infection.Conclusions: The WHOQOL-BREF is a valid outcome measure for assessing general quality of life for substance abusers in terms of physical, psychological, social, and environmental factors. It can also be used as a treatment outcome measure to evaluate the effect of treatments for substance abusers. However, the three misfit negatively worded items should be used with caution because the substance abuser may not fully understand their meaning. Future research may apply cognitive interviews to determine the cognitive functioning of substance abusers and their interpretation of negatively worded items.
AB - Background: The brief version of World Health Organization Quality of Life assessment (WHOQOL-BREF), a useful outcome measure for clinical decision making, has been evaluated using classical test theory (CTT) for psychometric properties on heroin-dependent patients. However, CTT has a major disadvantage of invalid summated score, and using Rasch models can overcome the shortcoming. The purpose of this study was using Rasch models to evaluate the psychometric properties of the WHOQOL-BREF for heroin-dependent patients, and the hypothesis was that each WHOQOL-BREF domain is unidimensional.Methods: Two hundred thirty six participants (24 females, mean [SD] age = 38.07 [7.44] years, first used heroin age = 26.13 [6.32] years), with a diagnosis of opioid dependence, were recruited from a methadone maintenance treatment program. Each participant filled out the WHOQOL-BREF. Parallel analysis (PA) and Rasch rating scale models were used for statistical analyses.Results: Based on the PA analyses, four domains of the WHOQOL-BREF were unidimensional. The Rasch analyses showed three negatively worded items (2 in Physical and 1 in Psychological) reported as misfits that may not contribute to the Physical and Psychological domains; one positively worded item in the Physical domain may be redundant. All values for the separation indices were above 2 except for the person separation index in the Physical domain (1.93). Category functioning and item independency of four WHOQOL-BREF domains were supported by the Rasch analyses, and there were 5 items showing the differential item function (DIF) for positive versus negative HIV (human immunodeficiency virus) infection.Conclusions: The WHOQOL-BREF is a valid outcome measure for assessing general quality of life for substance abusers in terms of physical, psychological, social, and environmental factors. It can also be used as a treatment outcome measure to evaluate the effect of treatments for substance abusers. However, the three misfit negatively worded items should be used with caution because the substance abuser may not fully understand their meaning. Future research may apply cognitive interviews to determine the cognitive functioning of substance abusers and their interpretation of negatively worded items.
UR - http://www.scopus.com/inward/record.url?scp=84908075284&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84908075284&partnerID=8YFLogxK
U2 - 10.1186/s12955-014-0148-6
DO - 10.1186/s12955-014-0148-6
M3 - Article
C2 - 25277717
AN - SCOPUS:84908075284
VL - 12
JO - Health and Quality of Life Outcomes
JF - Health and Quality of Life Outcomes
SN - 1477-7525
IS - 1
M1 - 148
ER -