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| Name | Class |
|---|---|
| Hong Kong Council on Smoking and Health | OTHER |
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The goal of this trial is to learn if chatbot-based instant messaging works to help smoking cessation in general adult smokers. It will also learn about the experience, attitude, and perception of using an LLM-based chatbot. The main questions it aims to answer are:
Researchers will compare an LLM-based chatbot smoking-cessation intervention to a human-led instant messaging support group (brief advice based on AWARD and personalised active referral) to determine whether chatbot-based instant messaging support promotes smoking cessation.
Participants in the intervention group will receive:
Although smoking prevalence in Hong Kong has declined to 9.1% in 2023, achieving the government's target of 7.8% by 2025 remains a major public health challenge. Unassisted "cold turkey" quitting has a long-term success rate of less than 5%, whereas evidence-based behavioural and pharmacological interventions can raise success rates to approximately 20% or higher. However, existing cessation services in Hong Kong face a critical utilisation gap: only 17.5% of smokers have engaged with professional services, and merely 23% have used nicotine replacement therapy. This underutilisation suggests that traditional human-resource-intensive models may lack accessibility, scalability, and local appeal. Generative AI, particularly large language models, offers a transformative solution by delivering consistent, scalable, and personalised support. In the 2025 "Quit to Win" round, investigators integrated an LLM-based chatbot via WhatsApp and received positive qualitative feedback. Yet quantitative analysis revealed a sharp decline in engagement, with weekly participation dropping from 32% in week 1 to 14% by week 12, indicating that conversational ability alone does not guarantee sustained user commitment. To address this implementation gap, investigators have developed an engagement-focused GenAI companion that incorporates structured onboarding, context-aware personalisation, multimodal (text/audio) input, empathetic support, habit-aligned reminders, localised humour, and gamified features such as success stories and knowledge quizzes. Therefore, the current study aims to test, via a two-arm non-inferiority randomised controlled trial, the effectiveness of a comprehensive intervention combining brief cessation advice (AWARD), personalised active referral, and this engagement-enhanced GenAI chatbot support compared with human-led instant messaging counselling among current smokers who join the Quit to Win Contest across all 18 districts of Hong Kong.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Intervention group | Experimental |
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| Control group | Active Comparator |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| AWARD advice | Behavioral | A brief (30-60 seconds) face-to-face or remote smoking cessation advice delivered using the validated AWARD model: Ask about smoking history; Warn about high health risks (accompanied by a health warning leaflet); Advise quitting as soon as possible and setting a quit date (to qualify for contest prizes); Refer to smoking cessation services using a referral card; Do it again - repeat the intervention at each follow-up, encouraging re-quitting after relapse or relapse prevention after success. |
| Measure | Description | Time Frame |
|---|---|---|
| Biochemically validated abstinence | Defined as exhaled CO level <4ppm and saliva cotinine level ≤30 ng/ml | 6-month follow-up |
| Measure | Description | Time Frame |
|---|---|---|
| Biochemically validated abstinence | Defined as exhaled CO level <4ppm and saliva cotinine level ≤30 ng/ml | 3-month follow-up |
| Self-reported 7-day point prevalence abstinence | Smokers who did not smoke even a puff in the 7 days preceding the follow-up |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Man Ping Wang, PhD | Contact | +852 3917 6636 | mpwang@hku.hk | |
| Yilan Wu | Contact | +852 56497578 | visspalan@connect.hku.hk |
| Name | Affiliation | Role |
|---|---|---|
| Man Ping Wang | The University of Hong Kong | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Hong Kong Council on Smoking and Health (COSH) | Hong Kong | Hong Kong | 999077 | Hong Kong |
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| Brief leaflet on health warning and smoking cessation | Behavioral | A two-sided, colour-printed A4 leaflet covering: (1) absolute risk of death from smoking; (2) full list of diseases caused by active and second-hand smoking; (3) ten pictorial warnings of health consequences on one page for maximum impact; (4) benefits of smoking cessation; and (5) simple encouraging messages to quit. |
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| Referral card | Behavioral | A three-folded card containing brief information and highlights of existing smoking cessation services in Hong Kong, contact methods, motivational messages, and strong supporting slogans. |
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| Self-help smoking cessation booklet | Behavioral | A generic booklet provided covering: benefits of quitting, smoking-related diseases, methods to quit, how to handle withdrawal symptoms, a quitting declaration, and other practical tips. |
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| Personalized active referral | Behavioral | Smokers will be introduced to various SC services in Hong Kong (via the referral card) and motivated to use them. Well-trained SC ambassadors will assist smokers in choosing their favourite or most convenient type of service. Research staff will assist participants in booking or re-booking the SC services at the 1- and 2-month follow-ups (after very brief questionnaire surveys). Participants' contact information will be forwarded to SC service providers within 7 days, and providers are expected to contact participants within 1-2 weeks. Research staff will also monitor participants' use of SC services at each follow-up (1-, 2-, 3-, and 6-month) and, at the 1- and 2-month follow-ups, assist participants in booking or rebooking appointments if necessary. Investigators shall liaise with existing service providers and seek their assistance in promptly supporting our smokers. |
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| 12 weeks of chatbot-based instant messaging support | Behavioral | Participants in the intervention group will receive 12 weeks of instant messaging support delivered by an LLM-based chatbot (GPT-4o or newer) on WhatsApp, supporting text and audio input. Using prompt engineering, agent techniques, and Retrieval-Augmented Generation, the chatbot delivers theory-based 5As/5Rs-structured interventions alongside freeform, on-demand support, with engagement features including personalisation, proactive check-ins, and interactive Quick Commands. |
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| 12 weeks of human-led instant messaging support | Behavioral | Participants in the control group will receive 12 weeks of instant messaging support delivered by a trained human counsellor via WhatsApp. Using the same theoretical frameworks as the chatbot intervention, the counsellor will provide real-time behavioural and psychosocial support grounded in the 5As/5Rs models, Motivational Interviewing (MI), and evidence-based Behaviour Change Techniques (BCTs). The support will be personalised according to each participant's sociodemographic characteristics, smoking patterns, quit intentions, and plans. |
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| Reminder messages | Behavioral | WhatsApp messages on follow-up survey reminders. |
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| 3- and 6-month follow-ups |
| Self-reported reduction | Defined by at least 50% reduction in baseline daily number of cigarettes | 1-, 2-, 3- and 6-month follow-ups |
| Self-reported use of smoking cessation service | Use of smoking cessation service at 1-, 2-, 3- and 6-month follow-ups. | 1-, 2-, 3- and 6-month follow-ups |
| Prolonged abstinence | Abstinence from smoking for 3 consecutive months at 3-month follow-up, or for 6 consecutive months at 6-month follow-up | 3-month and 6-month follow-ups |
| Quit attempt | Abstinence for at least 24 hours | 1-, 2-, 3-, and 6-month follow-ups |
| Post-cessation weight change | Self-reported change in body weight (in kilograms) from baseline to follow-up | 6-month follow-up |
| Self-reported mental health conditions | Patient Health Questionnaire-4 (PHQ-4): The PHQ-4 is a 4-item ultra-brief screening tool for anxiety and depression that combines the GAD-2 and PHQ-2 subscales. Each item is scored 0-3, with a total score of 0-12; subscale scores of 3 or higher indicate positive screening and warrant further clinical assessment. | Baseline and 6-month follow-up |
| Self-reported smoking-related health conditions | Answer "Yes" to experiencing any smoking-related health condition during smoking cessation or reduction | Baseline and 6-month follow-up |
| Chatbot user experience | Chatbot Usability Scale, or the 11-item Bot Usability Scale (BUS), is a validated questionnaire that evaluates chatbot usability across five dimensions (accessibility, function quality, conversation/information quality, privacy/security, and response time) using a 5-point Likert scale. The total score (11-55) is the sum of all items; a higher total score indicates better overall usability and greater user satisfaction. Higher scores on individual dimensions similarly reflect superior performance in those areas. | 3-month follow-up |
| ID | Term |
|---|---|
| D016540 | Smoking Cessation |
| ID | Term |
|---|---|
| D015438 | Health Behavior |
| D001519 | Behavior |
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