How to set standards for outcomes in alcohol brief intervention trials: ORBITAL protocol

What is it about?

lcohol brief interventions (ABIs) are delivered across a wide range of settings and have been studied extensively, yet the evidence base is weakened by the sheer variety of outcomes measured and the inconsistency with which they are reported across trials. The ORBITAL (Outcome Reporting in Brief Intervention Trials: Alcohol) project was established to address this by developing a core outcome set (COS), a minimum agreed standard for which outcomes should be measured and reported in future ABI trials. This protocol paper, published in Trials in 2017, sets out the full methodology for the project. It describes the three-stage approach: a systematic review to map all outcomes used in existing ABI efficacy and effectiveness trials and assess their measurement properties using COSMIN criteria; a multi-round international Delphi study to prioritise outcomes involving researchers, clinicians, policymakers and people with lived experience; and a final consensus meeting. The project was convened through INEBRIA, the International Network on Brief Interventions for Alcohol and Other Drugs.

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Why is it important?

Core outcome sets are a well-established solution to the problem of outcome heterogeneity in clinical trial evidence, yet no COS had been developed for alcohol brief interventions despite decades of research in the field. Without a shared standard, systematic reviews of ABI evidence are forced to combine incompatible outcomes, obscure meaningful differences between trials, and produce unreliable conclusions about effectiveness. Publishing the protocol in advance is itself a methodological best practice, allowing scrutiny of the approach before results are generated and reducing the risk of undisclosed outcome switching. The paper established the scientific and governance foundations for the ORBITAL consensus process, which subsequently involved over 150 stakeholders from 19 countries and culminated in the 2021 core outcome set publication.