Mobile Chat Messaging for Smoking Relapse Prevention: A Randomized Clinical Trial
Adding mobile chat counseling to usual care improved 6-month biochemically confirmed abstinence in recent quitters compared with low-intensity text messages.
*Randomized clinical trial; Level 1b (OCEBM).
*Randomized clinical trial; Level 1b (OCEBM).
Citation
Luk TT, Su X, Wong V, et al. Mobile Chat Messaging for Smoking Relapse Prevention: A Randomized Clinical Trial. JAMA Internal Medicine. 2026;186(3):294-302. doi:10.1001/jamainternmed.2025.7439.
Background
Most people who quit smoking return to smoking, often within the first weeks. Scalable relapse-prevention support is limited, and mobile messaging could extend help beyond clinic visits.
Patients
590 adults in Hong Kong cessation services who had stopped smoking for 3–30 days and previously smoked daily. Excluded: participation in other cessation studies, diagnosed mental health condition, or regular use of psychiatric medicines; required a smartphone with the messaging app installed.
Intervention
Usual cessation treatment plus 3 months of chat-based relapse support: live counselor messaging (work hours) and access to a supportive chatbot.
Control
Usual cessation treatment plus 8 generic text messages over 3 months.
Outcome
Primary: biochemically validated abstinence at 6 months (exhaled carbon monoxide <5 parts per million or negative saliva cotinine test). Secondary: self-reported prolonged abstinence, 7-day abstinence, and relapse (7 consecutive smoking days) at 6 months.
Follow-up Period
6 months.
Results
| 6-month outcome | Intervention | Control | Relative effect (95% CI) | NNT |
|---|---|---|---|---|
| Biochemically validated abstinence (primary) | 45.9% (135/294) | 35.5% (105/296) | Relative risk 1.29 (1.06–1.58) | 10 |
| Self-reported prolonged abstinence | 57.5% (169/294) | 47.6% (141/296) | Relative risk 1.21 (1.03–1.41) | 10 |
| Self-reported 7-day abstinence | 65.6% (193/294) | 54.7% (162/296) | Relative risk 1.20 (1.05–1.37) | 9 |
| Relapse | 33.0% (97/294) | 44.9% (133/296) | Relative risk 0.73 (0.60–0.90) | 9 |
Analyses were intention-to-treat, with missing outcomes counted as relapse.
Limitations
Participants and counselors could not be blinded. Results may not generalize well beyond mostly male, clinic-linked recent quitters, or to people with mental health conditions (excluded). A local tobacco tax increase may have raised quit rates in both groups. One counselor delivered the intervention, and tests may miss exclusive use of some non-smoked nicotine products.
Funding
Hong Kong government Health and Medical Research Fund; no funder role reported.
Clinical Application
Add counselor-guided chat relapse support for recent quitters already in cessation care; expect about 1 extra confirmed quitter per 10 treated versus minimal texting.
Discussion
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In this assessor-blinded randomized clinical trial, mobile chat messaging increased 6-month biochemically validated abstinence vs generic texts (45.9% vs 35.5%; RR 1.29; NNT 10). How valid and applicable are these results for your smoking-cessation population, and would they change practice? In this randomized trial, validated abstinence was 45.9% with mobile chat messaging and 35.5% with generic text messaging, with RR 1.29. Which interpretation best distinguishes the relative and absolute effects?