Longitudinal association of preference-weighted health-related quality of life measures and substance use disorder outcomes

Aim To examine the construct validity of generic preference‐weighted health‐related quality of life measures in a sample of patients with a substance use disorder (SUD). Design Longitudinal (baseline and 6‐month follow‐up) data from a research study that evaluated interventions to improve linkage and engagement with SUD treatment. Setting A central intake unit that referred patients to seven SUD treatment centers in a Midwestern US metropolitan area. Participants A total of 495 individuals with a SUD. Measurements Participants completed two preference‐weighted measures: the self‐administered Quality of Well‐Being scale (QWB‐SA) and the standard gamble weighted Medical Outcomes Study SF‐12 (SF‐6D). They were also administered two clinical assessments: all seven domains of the Addiction Severity Index (ASI) and a symptom checklist based on the DSM‐IV. Construct validity was determined via the relationships between disease‐specific SUD and generic measures. Findings In unadjusted analyses, the QWB‐SA and SF‐6D change scores were correlated significantly with six ASI subscale change scores, but not with employment status. In adjusted repeated‐measures analyses, three of seven ASI subscale scores were significant predictors of QWB‐SA and 5/7 ASI subscale scores were significant predictors of SF‐6D. Abstinence and problematic use at follow‐up were significant predictors of QWB‐SA and SF‐6D. Effect sizes ranged from 0.352 to 0.400 for abstinence and ?0.484 to ?0.585 for problematic use. Conclusions Generic preference‐weighted health‐related quality of life measures show moderate to good associations with substance‐use specific measures and in certain circumstances can be used in their stead. This study provides further support for the use of the Quality of Well‐Being scale and Medical Outcomes Study SF‐12 in clinical and economic evaluations of substance use disorder interventions.