Brief Interventions (BIs) for risky drinkers are an effective tool in primary care. Lack of time in daily practice has been identified as a barrier for the wide implementation of BI. There is growing evidence that e-health tools such as web based BIs can be an efficient alternative to standard face-to-face BIs and save time to general practitioners (GP).

The main aim of this study is to test non-inferiority of a web based BI for risky drinkers against a traditional face to face BI delivered by a general practitioner. We have designed a randomised controlled non-inferiority trial comparing both interventions, to be performed in primary care health centres in Catalonia, Spain.

Adults attending in primary care centres and willing to participate, will be invited to fill the short Alcohol Use Disorders Identification Test (AUDIT-C) in a specific website. Those screening positive and who accept to share the baseline data with their GP will be invited to an online assessment of their drinking and randomized to a standard BI with their GP or to the online BI.

Follow-up assessment will be conducted online at months 3 and 12, using the full Alcohol Use Disorder Identification Test (AUDIT) and the quality of life questionnaire (D5-EQD5). The main outcome will be the proportion of risky drinkers according to the AUDIT. Assuming a 30% reduction in the proportion of risky drinkers in the control group (classroom), allowing for an overall attrition of 10% of patients in the trial and non-inferiority assessed against a specified margin of 10%, it is estimated that 500 patients would be required in each group to give the test a 90% power (1-β) to reject the null hypothesis.

Trial design: A randomised non-inferiority controlled trial in primary care comparing facilitated access to a website for risky drinkers against a standard face-to-face BI. With the exception of the non-experimental intervention, all components of the study will be administered online to patients. Patients will be actively encouraged by their PHCP to access the application, which is available on the website of the programme 'Alcohol y Salud' (http:// www.alcoholysalud.cat), and will be provided with a unique registration code. The trial website is a Spanish adaptation of the English version of http://www.DownYourDrink.org.uk (DYD) developed in the UK, which includes modules for all the key trial components including screening, consent, assessment, randomisation and follow-up. It also incorporates the alcohol reduction website for the patients in the experimental group. The site has been adapted from the http://www.DownYourDrink.org.uk website developed for the DYD-RCT (randomised controlled trial).14 Details of DYD and the psychological theory that underpinned its development have been reported elsewhere. 21 Country-specific information such as recommended guidelines for alcohol intake, definitions of standard drinks and alcohol-related laws will be included. The website also incorporates a menu-driven facility to enable PHCP to customise automated messages to patients, for example, by adding photographs and pre-recorded messages. The personalised messages will appear to each patient using the log-in code provided by that practitioner.

Practitioner recruitment, training and incentives:

Recruitment will be based on the XaROH network. A 3 h seminar on new technologies, and EI and BI, introducing the trial, will be offered to all members of the XaROH, and those attending will be invited to sign up for the trial. In addition, several advertisements will be posted on the 'Beveu Menys' platform offering participation in the trial. In selecting practices, preference will be given to those with at least 5000 registered patients. Those practices that are selected as participants will be required to undergo a 1-day training programme. The training has four steps: (1) introduction to trial; (2) familiarisation with website; (3) update about EI and BI; and (4) practice in EI and BI (role-playing). Finally, participants will be encouraged to use the website and to tailor-make patient messages. Participating PHCPs will receive a financial incentive of €20 per patient recruited to the trial.

Inclusion Criteria:

• Patients aged 18 years old or over attended in primary care during the study period
• AUDIT-C 4 or above for women and 5 or above for men (in online screening)

Exclusion Criteria:

• Severe psychiatric disorders
• Serious visual impairment
• Terminal illness
• To have inadequate command of the Spanish or Catalan language
• AUDIT ≥ 18 in baseline assessment.

Excluded patients will be referred to GPs to consider other interventions.