Reducing hazardous alcohol consumption: an evidence synthesis

Around a quarter to a third of adults in England have health risk or harm due to heavy drinking. Most of this risk and harm is preventable if drinking is reduced. Two Cochrane reviews reported that digitally and verbally delivered interventions reduced hazardous and harmful alcohol consumption by 2·5 to 3·0 UK units per week. However, few trials have compared digitally and verbally delivered interventions directly. We aimed to inform policy and practice regarding efficient alcohol interventions for hazardous and harmful drinkers. We did a systematic review using standard methods. Literature searches from the two Cochrane reviews were updated and 164 studies included. We combined direct and indirect data in network meta-analyses to compare the effectiveness of digitally versus verbally delivered interventions, in any setting, that aimed to help people screened as having hazardous or harmful alcohol consumption to recognise and reduce their drinking. Outcomes were difference in mean weekly alcohol consumption and number of heavy episodic drinking occasions. We assessed the quality of the studies using the Cochrane risk of bias tool. We developed an economic model to compare the cost-effectiveness of the two types of interventions. This study is registered with Prospero, number CRD42018089609. At 6 months, 49 studies suggested that verbally delivered interventions were more successful in reducing consumption than digitally delivered interventions (–14 g per week, 95% CI –23 to –4). At 12 months, 46 studies suggested weaker evidence of a smaller reduction (–10 g per week, 95% CI –28 to 8). Little evidence was found of a difference in number of heavy episodic drinking occasions. The main sources of bias in the trials were attrition and performance bias. These results will be fed into a decision analytic model, along with treatment pathways and natural progression for five pertinent diseases, to compare the cost-effectiveness of digitally versus verbally delivered alcohol interventions. Verbally delivered interventions reduce alcohol consumption more, on average, than digitally delivered interventions. Further research should explore heterogeneity. National Institute of Health Research School for Public Health