Pretreatment ethyl glucuronide levels predict response to a contingency management intervention for alcohol use disorders among adults with serious mental illness.

Background And Objectives: This study investigated if pretreatment ethyl glucuronide (EtG) levels corresponding to light (100 ng/mL), heavy (500 ng/mL), and very heavy (1,000 ng/mL) drinking predicted longest duration of alcohol abstinence (LDA) and proportion of EtG-negative urine tests in outpatients receiving a 12-week EtG-based contingency management (CM) intervention for alcohol dependence.

Methods: Participants were 40 adults diagnosed with alcohol use disorders and serious mental illness who submitted up to 12 urine samples for EtG analysis during a 4-week observation period and were then randomized to 12-weeks of CM for alcohol abstinence and addiction treatment attendance. Alcohol use outcomes during CM as assessed by EtG and self-report were compared across those who did and did not attain a pre-treatment average EtG level of 500 ng/mL-a level that equates to frequent heavy drinking.

Results: Only the 500 ng/mL cutoff was associated with significant differences in LDA and proportion of EtG-negative samples during CM. Those with a pre-treatment EtG < 500 ng/mL attained a LDA 2.3 (alcohol) to 2.9 (drugs) weeks longer than pre-treatment heavy drinkers.

Discussion And Conclusions: The EtG biomarker can be used to determine who will respond to a CM intervention for alcohol use disorders and could inform future trials that are designed to be tailored to individual patients.

Scientific Significance: Results suggest pre-treatment EtG cutoffs equivalent to heavy and very heavy drinking predict outcomes in CM. (Am J Addict 2017;26:673-675).