We measured utilities for 6 of opioid misuse and treatment states, selected to represent a spectrum of states that would be useful for future cost-effectiveness analyses: active injection opioid misuse (“active injection misuse”); active prescription opioid misuse (“active prescription misuse”); methadone maintenance therapy at the initiation stage (“initiation methadone”), and when the user is considered stabilized in treatment (“stabilized methadone”); and buprenorphine therapy at the initiation stage (“initiation buprenorphine”), and when the user is considered stabilized in treatment (“stabilized buprenorphine”). Utilities are defined on a scale of 0-1.0, where zero=the value of being dead and 1.0=the value of being in perfect health, and all health states are valued relative to these endpoints. Utility is thus a universal metric that allows comparisons across diseases.
Utilities can be measured in a variety of ways: the “direct” method is to describe a health condition to someone in the general population – with or without personal experience with it--and have him/her assign it a number between 0 and 1.0. The “indirect” method is to have a person who has a condition report on his/her symptoms, health status, and functioning using a structured questionnaire (a “generic” utility instrument), and then to assign a utility value to this report using a pre-existing set of values collected from the general population.18 Broadly speaking, direct methods are considered theoretically superior but more administratively burdensome to implement than indirect methods; indirect methods are more convenient and can easily be integrated into clinical trials, but have practical limitations in their sensitivity to effects.19 (link),20 (link) Both methods produce theoretically equivalent results, although in practice differences across methods have been observed.21 (link)We used a direct method in this study, the “standard gamble” (SG).18 The SG asks a respondent to consider the risk of death s/he would be willing to take in order to avoid living in a particular health state, and assigns value to health on the 0-1.0 scale described above.18 For example, if someone would take 10% risk of death to avoid living with diabetes, the SG for diabetes would be 0.90, or 90% of the value of perfect health. The SG is considered the theoretically optimal method for estimating utilities for societal-perspective economic evaluation.6
Utilities can be measured in a variety of ways: the “direct” method is to describe a health condition to someone in the general population – with or without personal experience with it--and have him/her assign it a number between 0 and 1.0. The “indirect” method is to have a person who has a condition report on his/her symptoms, health status, and functioning using a structured questionnaire (a “generic” utility instrument), and then to assign a utility value to this report using a pre-existing set of values collected from the general population.18 Broadly speaking, direct methods are considered theoretically superior but more administratively burdensome to implement than indirect methods; indirect methods are more convenient and can easily be integrated into clinical trials, but have practical limitations in their sensitivity to effects.19 (link),20 (link) Both methods produce theoretically equivalent results, although in practice differences across methods have been observed.21 (link)We used a direct method in this study, the “standard gamble” (SG).18 The SG asks a respondent to consider the risk of death s/he would be willing to take in order to avoid living in a particular health state, and assigns value to health on the 0-1.0 scale described above.18 For example, if someone would take 10% risk of death to avoid living with diabetes, the SG for diabetes would be 0.90, or 90% of the value of perfect health. The SG is considered the theoretically optimal method for estimating utilities for societal-perspective economic evaluation.6
