Real-time Smoking Cessation Instant Messaging Support Using a Large Language Model (LLM)-Based Chatbot Via "Quit to Win" 2025 (QTW2025)

Not Applicable

Not yet recruiting

• Conditions: Smoking Cessation

• Registration Number: NCT06914492
• Lead Sponsor: The University of Hong Kong

Brief Summary

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:

1. Will LLM-based chatbot smoking cessation intervention have a higher validated abstinence rate than the control group?

2. Will LLM-based chatbot smoking cessation intervention have a higher self-reported abstinence rate, smoking reduction rate, and smoking cessation services use rate than the control group?

Researchers will compare LLM-based chatbot smoking cessation intervention to a usual care group (brief advice based on AWARD and personalized active referral) to see if chatbot-based instant messaging support works to promote smoking cessation.

Participants in the intervention group will receive:

1. AWARD advice

2. Personalized active referral

3. 12 weeks of chatbot-based instant messaging support (via WhatsApp)

Detailed Description

Although smoking prevalence is decreasing in Hong Kong (1982: 23.3%; 2023: 9.1%), it accounts for over 7,000 deaths per year and a large amount of medical cost, long-term care and productivity loss of US$ 688 million (0.6% Hong Kong GDP). Quitting is difficult because nicotine is highly addictive. Long-term habitual tobacco smoking could foster a series of physical and psychological dependence on nicotine, and thus induce cravings and nicotine withdrawal symptoms when remaining abstinent. Tradition "one-intervention-for-all" approach cannot work optimally for overall smoking population because of the individual differences in the background characteristic and variations in response to the intervention. Intervention approaches that account for personalization and variation should be explored.

Preliminary studies suggest that AI-based chatbots can deliver structured counseling to support tobacco cessation through personalised, empathetic, and authentic conversations, thus enhancing the effectiveness of smoking cessation interventions. When integrated into social media, AI chatbots can provide timely, targeted responses and connect users with a resources on widely used platforms. A 2023 meta-analysis involving 58,796 participants further highlighted the promise of chatbots for tobacco cessation (RR=1.29, 95%CI 1.13-1.46).

In late 2022, the release of ChatGPT revolutionized AI and large language models by offering unprecedented reasoning and conversational capabilities, which enables the development of more sophisticated, human-like chatbots. Although ChatGPT (and the GenAI in general) was trained as a general-purpose virtual assistant, its tasks-specific performance can be significantly enhanced through prompt engineering. Leveraging this approach, we developed an LLM-based chatbot to autonomously deliver smoking cessation support via WhatsApp according to established protocols. Our previous rule-based chatbot effectively prevented smoking relapse, and a pilot trial with an LLM-based chatbot for youth smokers (n=154) showed feasibility, achieving an 80.2% retention rate. These findings support the implementation of GenAI chatbots as promising tools for brief smoking cessation interventions in adult smokers.

Therefore, our study aims to test the effectiveness of a comprehensive intervention using brief cessation advice, personalized active referral, and chatbot-based instant messaging support compared with the control group on current smokers who join the Quit to Win Contest.

Study Timeline

• Study First Submitted: 2025-03-31
• Study First Submitted QC: 2025-03-31
• Study First Posted: 2025-04-06
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-08
• Last Update Posted: 2025-05-14
• Study Start: 2025-06-21
• Primary Completion: 2026-06-30
• Study Completion: 2027-06-30

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 1094

Inclusion Criteria

• Hong Kong residents aged 18 or above
• Smoke at least 1 tobacco stick (includes HTP) per day or use e-cigarette daily in the past 3-month
• Able to communicate in Chinese
• Exhaled carbon monoxide level ≥4 part per million or a positive salivary cotinine test
• Able to use the instant messaging tool (e.g., WhatsApp, WeChat) for communication

Exclusion Criteria

• Smokers who have communication barriers (either physical or cognitive).
• Smokers who are currently participating in other smoking cessation programs or services.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Biochemically validated abstinence	6-month follow-up	Defined as exhaled CO level \<4ppm and saliva cotinine level ≤30 ng/ml

Secondary Outcome Measures

Name	Time	Method
Biochemically validated abstinence	3-month follow-up	Defined as exhaled CO level \<4ppm and saliva cotinine level ≤30 ng/ml
Self-reported 7-day point prevalence abstinence	3- and 6-month follow-ups	Smokers who did not smoke even a puff in the 7 days preceding the follow-up
Self-reported reduction	1-, 2-, 3- and 6-month follow-ups	Defined by at least 50% reduction in baseline daily number of cigarettes
Self-reported use of smoking cessation service	1-, 2-, 3- and 6-month follow-ups	Use of smoking cessation service at 1-, 2-, 3- and 6-month follow-ups.

Trial Locations

Locations (1)

Hong Kong Council on Smoking and Health (COSH); 🇭🇰 Hong Kong, Hong Kong