Preference-weighted health status associated with substance use-disorders treatment

Measuring benefits of opioid misuse treatment for economic evaluation: health-related quality of life of opioid-dependent individuals and their spouses as assessed by a sample of the US population

AIMS

To understand how the general public views the quality of life effects of opioid misuse and opioid use disorder on an individual and his/her spouse, measured in terms used in economic evaluations.

DESIGN

Cross-sectional internet survey of a US population-representative respondent panel conducted December 2013-January 2014.

SETTING

United States.

PARTICIPANTS

A total of 2054 randomly selected adults; 51.1% male (before weighting).

MEASUREMENTS

Mean (95% confidence interval) and median health 'utility' for six opioid misuse and treatment outcomes: active injection misuse; active prescription misuse; methadone maintenance therapy at initiation and when stabilized in treatment; and buprenorphine therapy at initiation and when stabilized. Utility is a numerical representation of health-related quality of life used in economic evaluations to 'adjust' estimated survival to include peoples' preferences for health states. Utilities are determined by surveying the general population to estimate the value they assign to particular health states on a scale where 0 = the value of being dead and 1.0 = the value of being in perfect health. Spouse spillover utility is assigned to a spouse of an individual who is in a particular health state.

FINDINGS

Mean individual utility ranged from 0.574 [95% confidence interval (CI) = 0.538, 0.611] for active injection opioid misuse to 0.766 for stabilized buprenorphine therapy (95% CI = 0.738, 0.795), with other states in between. Female respondents assigned higher utility to the active prescription misuse and buprenorphine therapy at initiation states than did males (P < 0.05); all other states did not differ by respondent gender. Mean spousal utilities were significantly lower than 1.0 but mostly higher than individual utility, and were similar between male and female respondents.

CONCLUSIONS

In the opinion of the US public, injection opioid misuse results in worse health-related quality of life than prescription misuse, and methadone therapy results in worse health-related quality of life than buprenorphine therapy. Spouses are negatively affected by their partner's opioid misuse and early treatment.

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.