Preparation of the manuscript was supported in part by Grants U10AA11715, 11716, 11721, 11727, 11756, 11768, 11773, 11776, 11777, 11783, 11787, 11799, and 11773 and by career scientist awards K05AA014715, K05AA00133, K02DA00326, and K23AA0032 from the National Institute on Alcohol Abuse and Alcoholism (NIAAA).
Factors Affecting %CDT Status at Entry Into a Multisite Clinical Treatment Trial: Experience from the COMBINE Study
Version of Record online: 11 OCT 2006
Alcoholism: Clinical and Experimental Research
Volume 30, Issue 11, pages 1878–1883, November 2006
How to Cite
Anton, R. F. and Youngblood, M. (2006), Factors Affecting %CDT Status at Entry Into a Multisite Clinical Treatment Trial: Experience from the COMBINE Study. Alcoholism: Clinical and Experimental Research, 30: 1878–1883. doi: 10.1111/j.1530-0277.2006.00225.x
- Issue online: 11 OCT 2006
- Version of Record online: 11 OCT 2006
- Received for publication June 19, 2006; accepted July 18, 2006.
- Carbohydrate-Deficient Transferrin;
- Clinical Trial;
- COMBINE Study
Background: Carbohydrate-deficient transferrin (CDT) occurs as a higher percentage of normal transferrin (%CDT) in heavy drinkers. %CDT is used as a marker of both alcohol use disorder severity and treatment outcome both clinically and in treatment trials. Nevertheless, little is known about the parameters that predict which patients are %CDT positives at treatment entry. These parameters might include level of drinking, days of abstinence before testing, and severity of alcohol dependence before evaluation.
Methods: %CDT levels were collected before randomization from participants of the COMBINE Study, a large federally sponsored multisite clinical trial evaluating medications and behavioral therapies in alcohol-dependent outpatients. %CDT (assayed in a central laboratory) was available in 1,193 individuals for whom drinking history in the 30 days before testing and measures of alcoholism severity were documented. The effects of drinking history and alcohol severity were evaluated for prediction of a %CDT-positive test status.
Results: Less percent days abstinent (PDA) and more drinks per drinking day (DDD) were predictive of higher rates of %CDT-positive patients (maximum 67%). Up to 14 days of continuous abstinence before testing did not appear to significantly affect %CDT status. Rates of %CDT positives remained reasonably steady up to about 40% PDA. Years of drinking at dependence levels had an unexpected negative impact on %CDT-positive rates while previous treatment had a small but positive impact of %CDT-positive rates. ADS and DrInC scores had no predictive value over and above recent drinking amounts on %CDT status.
Conclusions: %CDT is more likely to be positive in those who have more days of drinking and to a lesser degree in those who drink more per drinking day. It can remain positive even in those alcoholic subjects who stop drinking many days before testing. Alcoholic subjects with more treatment experiences appear to have a marginally higher %CDT-positive rate.