Talk is cheap: measuring drinking outcomes in clinical trials

Area of Science:

• Addiction research
• Clinical trial methodology
• Alcohol use disorder assessment

Background:

• Accurate measurement of alcohol consumption is crucial for evaluating treatment efficacy in clinical trials.
• Discrepancies often exist between self-reports, biochemical markers, and collateral information regarding alcohol intake.

Purpose of the Study:

• To assess the agreement between self-reported drinking, biological indicators (e.g., liver function tests), and collateral informant reports.
• To identify patient characteristics associated with discrepancies among these data sources.

Main Methods:

• Utilized data from a large clinical trial (N=1,726) comparing alcohol treatment matching.
• Compared self-reports, biological indicators, and collateral reports at treatment admission and 12-month follow-up.

Main Results:

• Self-reports and collateral reports showed high agreement at admission (97.1%).
• Liver function tests (serum gamma-glutamyl transpeptidase) were insensitive, detecting heavy drinking in only 39.7% of cases.
• Agreement between self-reports and biochemical measures improved at follow-up, but self-reports remained more sensitive to drinking levels.
• Patients with discrepancies often had severe drinking problems, prior treatments, and cognitive impairment.

Conclusions:

• Biochemical tests and collateral reports offer limited added value over self-reports in clinical trials with volunteers.
• Resources may be better allocated to enhancing the validity of self-report measures through improved interview techniques.