Smoke is still a significant Public Health problem. The Emergency Departments (EDs) could be the ideal setting to set up smoke cessation interventions (high prevalence of smoking patient compared to the general population). The structured brief counseling 5As based (ask, advice, asses, assist, arrange) is an effective Public Health intervention when performed by the General Practitioners. Still not clear is its feasibility and effectiveness in the ED setting. Aim of the study. To assess the feasibility and effectiveness of the 5As based counselling in the University ED of Novara compared to the "usual care".

The study is a Randomized Controlled Trial performed in Novara (Piedmont, Italy) in the ED of the "Maggiore della Carità" University Hospital and involving the Treatment Center for Tobacco use (CTT) of the Addiction Department of the Local Health Unit of Novara (ASL NO).

The RCT has two parallel groups (allocation 1:1): the intervention group and the controll group.

Adult smokers attending ED of the "Maggiore della Carità" University Hospital of the city of Novara are invited to participate to the intervention.

The intervention consists in the "5As" smoke cessation brief structured counselling performed by the ED nurses. The 5As counselling is composed by 5 main steps:

1. Ask: every patient is asked whether he/she is or is not a smoker in order to identify those who could benefit from the counseling;
2. Advice: the patient is advised to quit in a strong, clear and personalized way;
3. Assess: the patient is asked if he/she would like to quit and it is assessed the strength of his/her dependence in order to tailor the following step on the patient's situation and readiness to quit;
4. Assist: all the patients receive the counseling by the nurse and those interested in quitting are assisted in their attempts. Furthermore patients are asked whether they want to be contacted by the CTT in order to start an intensive treatment;
5. Arrange: for the patients willing to make a quit attempt, it is aimed to arrange for follow up contact by the CTT and to start a treatment in the CTT. It is expected also to prevent or treat eventual relapses.

The controll group received no intervention ("usual care" that could range between not mentioning the subject at all, to a general advice to quit without bringing any structured counselling).

All the nurses involved in the project as "intervention providers" will receive a proper training carried out by the CTT staff. The training will be focused on:

• the description and application of the 5As intervention;
• the importance of the relationship with patients;
• the acquisition of specific skills through role playing techniques.

The sample size needed is 1200 patients (600 for each arm of the study). This sample size has been calculated assuming that:

• in Italy the annual cessation rate in the general population is 8.4% (Istituto Superiore di Sanità, 2015);
• that the relative risk of 12-month point-estimated tobacco abstinence in the intervention group compared to the general population is 1.6.

The calculation was based on desired significance level of 5% (two-tailed) and power of 80%.

The evaluation of the feasibility and sustainability of the intervention is descriptive and the investigators did not include it in the power calculation.

Data collection. Data about patients are collected as follow:

• through the ED software; the ED software records all the clinically relevant information (triage, visit, observation and monitoring, if needed, or discharge);
• from the baseline questionnaire. Patients from both groups will be given a questionnaire about their smoking habits in order to collect data about their health status, socio-demographic characteristics, their degree of addiction by using the Fagerström test and their orientation with respect to the possibility of quitting. The questionnaire is the adaptation of the already validated questionnaire of the FRITT project, implemented in Sweden from the Karolinska Institutet, with the addition of the Fageström test for nicotine dependence. It also takes inspiration from the questionnaire SPRINT.
• from the nurse checklist. The check list is filled by the nurses involved in the study at the moment of the contact with the patients of the intervention group. The check list is aimed to investigate if the intervention has been carried out and in detail which steps have been performed. In the event that the intervention had not been carried out, the reason for this is collected in the check list;
• from the follow up- questionnaire. The follow-up questionnaire is administered by telephone at 6 and 12 month in order to collect the informations about the outcomes. Participants in the follow-up phase will be contacted by telephone at least 3 times at different hours of the day, in order to maximize the possibilities to get an answer.
• from the CTT software for those who decided to proceed with the intensive treatment.

All the data collected are recorded in the Research Electronic Data Capture (RedCap). RedCap is a secure web application that ensures the confidentiality of the data and high privacy levels, according to the Italian law.

Results will be analyzed with "intention-to treat" principle: each patient will be considered under original randomization no matter what counseling he/she actually received. In secondary analyzes, the investigators will perform both "per protocol" and "as treated" analyses.

Data monitoring. Due to the short duration of the trial and to the lack of recognized collateral effects, there is no need of a data monitoring committee.

The project does not implicate any physical intrusion or risk for participants.

Consent or assent is obtained first orally by the triage nurse than written by a designated person.

Access to data. The only actors who will have access to the final trial dataset are the researchers of Eastern Piedmont University involved in the study and the CTT physicians who collaborated at the study.

Inclusion Criteria:

• self-statement as "current smokers" (at least one cigarette per day) during the triage interview;
• age ≥ 18;
• priority code urgency (yellow code) or deferrable urgency (green code) or non-urgency (white code);
• provision of an informed consent.

Exclusion Criteria:

• priority code emergency (red code);
• altered mental status or history of psychiatric illness;
• inability to understand either written or oral Italian;
• patient already in treatment or follow-up for tobacco addiction;
• patient allocated to a nurse who has not been trained in counseling and does not participate to the study;
• informed consent denied

Patients do not know in which group they were randomized