One month follow-up outcomes of a transdermal alcohol concentration-based contingency management intervention to reduce heavy drinking among driving while intoxicated arrestees

Background: High rates of driving while intoxicated persist, and recidivism is common. Recently, we demonstrated that 8 weeks of transdermal alcohol concentration (TAC)-based contingency management (CM) reduced heavy drinking (≥5 [men] or ≥4 [women] standard drinks) in 145 DWI arrestees under pretrial supervision. Here, we report 1-month (postintervention) follow-up outcomes for a subgroup of participants who were not Mandated to wear transdermal alcohol monitors. Methods: After the intervention, Non-Mandated participants (n = 100, 69%) returned for a 1-month follow-up visit and self-reported drinking during the previous month. Also, a fingerstick blood sample was used to measure the alcohol use biomarker phosphatidylethanol (PEth). PEth was measured by HPLC-MS/MS, with levels <20 ng/mL indicating low or no drinking. Multiple logistic regression models compared drinking outcomes (≤1 drinking day or ≤1 heavy drinking day) between the CM and Control groups (controlling for age, sex, White/non-White and drinking frequency prior to study entry). Results: Analyses showed that CM group participants were more likely to self-report ≤1 day of any drinking than those in the Control group (OR = 3.07, p = 0.03) and more likely to have ≤1 heavy drinking (OR = 4.13, p = 0.04). PEth results were consistent with the self-report, even though a nonsignificant trend toward a greater likelihood of having PEth levels <20 ng/mL was observed in the CM compared with the control group (OR = 2.29, p = 0.11). Conclusions: Outcomes observed after an 8-week TAC-based CM intervention appeared to persist for 1 month after a TAC-based CM intervention. Participants in the CM intervention group were more likely to have fewer drinking days and fewer heavy drinking days, as evidenced by self-reported drinking that was consistent with PEth levels <20 ng/mL.