BACKGROUND

Internet-based interventions for heavy drinkers show promising results, but existing research is characterized by few studies in nonstudent adult populations and few comparisons with appropriate control groups.

OBJECTIVE

To test whether a fully automated Internet-based brief personalized feedback intervention and a fully automated Internet-based personalized brief advice intervention in a non-treatment-seeking population of heavy drinkers would result in a reduced alcohol intake.

METHODS

We conducted a 3-arm parallel randomized controlled trial in a general population-based sample of heavy drinkers. The 54,157 participants (median age of 58 years) were screened for heavy drinking. Of the 3418 participants who had a weekly alcohol consumption above 14 drinks for women and 21 drinks for men, 1380 (619 women) consented to take part in the trial and were randomly assigned to an Internet-based brief personalized feedback intervention group (normative feedback, n = 476), an Internet-based personalized brief advice intervention group (n = 450), or a nonintervention control group (n = 454). Follow-up after 6 and 12 months included 871 and 1064 participants, respectively, of all groups combined. The outcome measure was self-reported weekly alcohol consumption. We analyzed the data according to the intention-to-treat principle. To examine changes over time and to account for the multiple time measurements, we used a multilevel linear mixed model. To take attrition into account, we used multiple imputation to address missing data.

RESULTS

The intervention effect of the Internet-based brief personalized feedback intervention, determined as the mean additional difference in changes in alcohol consumption in the Internet-based brief personalized feedback intervention compared with the control group, was -1.8 drinks/week after 6 months and -1.4 drinks/week after 12 months; these effects were nonsignificant (95% confidence interval -4.0 to 0.3 at 6 months, -3.4 to 0.6 at 12 months). The intervention effect of the Internet-based personalized brief advice intervention was -0.5 drinks/week after 6 months and -1.2 drinks/week after 12 months; these effects were nonsignificant (95% confidence interval -2.7 to 1.6 at 6 months, -3.3 to 0.9 at 12 months).

CONCLUSIONS

In this randomized controlled trial we found no evidence that an Internet-based brief personalized feedback intervention was effective in reducing drinking in an adult population of heavy drinkers.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00751985; http://clinicaltrials.gov/ct2/show/NCT00751985 (Archived by WebCite at http://www.webcitation.org/68WCRLyaP).