Too many outcomes, no consistency: review of alcohol brief intervention trials measurement

What is it about?

Alcohol brief interventions (ABIs) are widely used in health care and community settings to help people reduce risky drinking, but the field's evidence base is weakened by striking inconsistency in what outcomes are measured and how they are reported. This systematic review searched ten databases for ABI efficacy and effectiveness trials published between January 2000 and November 2017, screening for studies meeting NICE public health guidance definitions. Across 401 included articles, the review catalogued 2,641 distinct outcomes measured using 1,560 different approaches, organised into seven a priori domains: biomarkers, alcohol-related outcomes, economic factors and resource use, health measures, life impact, intervention factors, and psychological and behavioural factors. The scale of variability identified makes cross-trial comparison and meta-analysis extremely difficult, and the review provides the most comprehensive mapping of ABI outcome reporting ever undertaken to inform the development of a standardised core outcome set.

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Why is it important?

The sheer scale of outcome heterogeneity documented here, 2,641 outcomes measured 1,560 different ways across 401 trials, makes the case for standardisation more powerfully than any previous argument in the field. This review is the first phase of the ORBITAL (Outcome Reporting in Brief Intervention Trials: Alcohol) project, which led directly to the international e-Delphi study and ultimately the ORBITAL core outcome set published in 2021 and now internationally recognised as the standard for ABI trial design. Without first mapping the full extent of the problem, the case for a mandated minimum outcome standard could not have been made. For policymakers and funders, the review demonstrates the extent to which investment in ABI research has produced findings that cannot be meaningfully synthesised, and makes the case that future trials designed without a common outcome framework risk perpetuating the same problem.