In the funded parent grant (R01-AA014988-13), we are examining the effects of an 8-week contingency management procedure using transdermal alcohol monitoring to reduce drinking among 440 individuals arrested for driving while intoxicated (DWI). The current application is a timely and cost-effective competitive revision proposing to add the measurement of an alcohol-use biomarker, phosphatidylethanol (PEth). The goals of this project are to extend our previous work by determining the extent to which PEth can be used to: (a) confirm abstinence, (b) characterize alcohol consumption levels, and (c) enhance the parent grant?s ability to objectively characterize drinking levels during post-intervention follow-up. There is a need for alcohol biomarkers that can objectively identify alcohol use (or confirm abstinence) and characterize individuals? patterns of drinking. PEth, measured in whole blood, has unique characteristics that make it a sensitive biomarker for alcohol use. Our recent pharmacokinetic study showed that PEth 16:0/18:1 (a homologue of PEth) can be used to detect as little as 1 to 2 standard alcohol drinks, supporting the notion that it may be useful in confirming alcohol abstinence (Javors et al., 2016). Furthermore, Ulwelling and Smith (2018) proposed that cut-off values of PEth 16:0/18:1 may be clinically useful in identifying alcohol-use drinking levels, including: none/light (< 20 ng/ml), moderate (20?199 ng/ml), and heavy (> 200 ng/ml). However, because these values were derived from a literature review, they require further validation. Our recent work also demonstrated that PEth 16:0/18:1 has a relatively long window of detection (half-life = 7.8 days) and can be detected up to 28 days after the last drink. These data provide indirect support for the idea that PEth 16:0/18:1 could be used as a marker for characterization of long-term drinking levels. In contrast, we have shown that PEth 16:0/20:4 has a much shorter half-life of 2.1 days, which may be more advantageous for characterizing recent drinking. The parent grant is monitoring alcohol consumption via transdermal alcohol monitoring during a contingency management intervention among individuals arrested for DWI. It includes post-intervention visits that rely on self-reported drinking. We propose to now include measurement of PEth 16:0/18:1 and 16:0/20:4 to address the gaps discussed above and characterize levels of drinking during the post-intervention period. We will collect blood samples weekly during the 8-week intervention phase of the study and during the post-intervention visits (3, 6, 9, and 12 months). Our revison primary aims are: to determine the accuracy of PEth 16:0/18:1 for detecting and identifying patterns of alcohol consumption (verified by transdermal alcohol monitoring); to develop and validate an algorithm for PEth 16:0/20:4 (shorter half-life) to detect and identify patterns of consumption (verified by transdermal alcohol monitoring); to use both homologues to identify heavy drinkers; and finally include measurement of PEth homologues during post-intervention visits of the parent grant to objectively characterize drinking levels.
Public Health Significance: Excessive alcohol consumption is the third-leading preventable cause of death in the United States. The proposed study will identify the clinical utility of a promising new alcohol biomarker, phosphatidylethanol, and determine how it may be used to confirm abstinence and better identify patterns of drinking. The results of this study lay the foundation for future work that will result in the application of alcohol- use biomarkers in prevention and treatment programs.
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