This randomized controlled trial will evaluate whether a 6-month behavioral intervention delivered via Telegram messenger increases smoking cessation rates in patients after myocardial infarction (MI).

Adult smokers hospitalized with acute MI who regularly use Telegram will be randomly assigned to either:

• INTERVENTION GROUP: Standard care plus a 6-month Telegram chatbot program providing personalized motivational messages, cognitive-behavioral techniques for craving management, and relapse prevention support.
• CONTROL GROUP: Standard care (routine physician advice to quit smoking) plus basic surveys via Telegram without therapeutic content.

The primary outcome is 30-day point prevalence abstinence at 6 months, verified by blinded telephone interview with participant and corroborating report from a close relative. Secondary outcomes include changes in cigarette consumption, nicotine dependence, motivation, and intervention engagement metrics.

This study addresses the critical gap in smoking cessation support after hospital discharge and could provide evidence for a scalable digital health solution in cardiac secondary prevention.

The TELEGRAM-MI trial is a multicenter, randomized, controlled, assessor-blinded superiority study testing a digital behavioral intervention for smoking cessation in post-myocardial infarction patients.

BACKGROUND: Smoking cessation is the most effective modifiable risk factor for reducing mortality after MI, yet long-term abstinence remains challenging due to limited sustained support. Digital interventions using popular messaging platforms offer a scalable solution to bridge the post-discharge support gap.

OBJECTIVES:

Primary: To determine if a 6-month Telegram chatbot intervention increases 30-day point prevalence abstinence rates at 6 months compared to standard care alone.

Secondary: To examine associations between baseline characteristics (nicotine dependence, motivation), engagement metrics, and cessation success; and to assess intervention acceptability.

METHODS: Approximately 142 participants will be recruited from inpatient cardiology departments. After providing informed consent, participants will be randomized 1:1 via the chatbot to either the intervention group (standard care plus 6-month behavioral support) or control group (standard care plus data collection only). The intervention incorporates evidence-based techniques including motivational messaging, cognitive-behavioral strategies, and relapse prevention protocols.

OUTCOMES: The primary outcome is biochemically unverified 30-day point prevalence abstinence at 6 months, assessed via blinded telephone interview with participant and relative verification. Secondary outcomes include various smoking behavior metrics collected through the chatbot platform.

ANALYSIS: Primary analysis will follow intention-to-treat principles, with missing data imputed as smoking. Statistical analyses will include chi-square tests for primary outcome and regression models for secondary outcomes.

POTENTIAL IMPACT: If effective, this intervention represents a readily implementable, low-cost strategy to enhance secondary prevention in cardiac patients.

Inclusion Criteria:

• Willing and able to provide written informed consent.
• Age 18 years or older.
• Hospitalization with a confirmed diagnosis of acute myocardial infarction (MI), including both ST-elevation MI (STEMI) and non-ST-elevation MI (NSTEMI).
• Current smoker at the time of index MI: self-reported smoking of at least one cigarette per day in the month prior to hospitalization.
• Regular user of the Telegram messenger application (app installed on a personal smartphone).
• Possession of a smartphone with internet access and a valid phone number.
• Ability and willingness to provide contact information for a close relative or cohabiting person who can verify smoking status at follow-up.

Exclusion Criteria:

• Smoking cessation more than 1 month prior to the index MI hospitalization.
• Physical or cognitive impairment that prevents the use of a smartphone (e.g., severe visual/hearing impairment, inability to read or respond to messages).
• Inability to read and understand the Russian language fluently.
• Comorbid condition with a life expectancy of less than 1 year.
• Active severe mental illness (e.g., psychosis, severe untreated depression) that would impede understanding of the protocol or adherence.
• Unwillingness or inability to provide contact details for a close relative for outcome verification.

All individual participant data collected during the trial, after de-identification, will be shared. This includes demographic data, smoking history, questionnaire responses (Fagerström Test, Importance/Confidence scales), intervention engagement metrics, and primary/secondary outcome data.

Beginning 12 months after main results publication and ending 5 years after publication. Data will be available for this period.

Data will be available to researchers who provide a methodologically sound research proposal approved by an independent review committee. Proposals should be directed to the corresponding author. Requestors will need to sign a data access agreement specifying the purpose of analysis, commitment to secure data handling, and agreement not to attempt re-identification of participants.

The outcome assessor conducting the 6-month telephone interview to ascertain smoking status is blinded to the participant's group assignment. The assessor has no access to the allocation data or the participant's interaction history with the Telegram bot. Participants are not explicitly informed of their group strategy but cannot be fully blinded due to the nature of the intervention.