Impact of Smoking Status on Major Adverse Cardiovascular Events in STEMI Patients: A Retrospective Cohort Study in Western Iran.

Q: What are the key findings of this study?

After adjusting for confounding factors, heavy smoking (≥15 pack-years) was not associated with a reduced risk of 1-year mortality compared to never smoking in patients with STEMI (HR 0.92).

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: ST-elevation myocardial infarction (STEMI) (n=645). Intervention: Heavy smoking (≥15 pack-years) vs. Never-smokers. Primary outcome: All-cause 1-year mortality (HR 0.92, 95% CI 0.28-3.02, p=0.896).

Q: What does this research mean for the field?

The apparent survival advantage of smoking in STEMI patients (the smoker's paradox) is explained by confounding factors such as younger age and fewer comorbidities, with smoking conferring no independent reduction in 1-year mortality or major adverse cardiovascular events. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.NEUTRAL.

Parisa Janjani; Nahid Salehi; Sayeh Motevaseli; Atiyeh Asadmobini

doi:10.48305/arya.2026.45612.3094

January 1, 2026Open Access

Impact of Smoking Status on Major Adverse Cardiovascular Events in STEMI Patients: A Retrospective Cohort Study in Western Iran.

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Key result

Heavy smoking shows no association with reduced 1-year mortality after STEMI compared to never smoking.

HR 0.92
95% CI 0.28-3.02
P=0.896
n=645

Figures

Why the study?

Whether smoking status and cumulative exposure influence prognosis after STEMI in the era of timely reperfusion and intensive secondary prevention remains uncertain, especially in populations with very high smoking rates.

Does smoking status and cumulative exposure influence 1-year mortality and MACE in STEMI patients undergoing contemporary treatment?

Key Points

To evaluate the association between smoking status, cumulative tobacco exposure, and major adverse cardiovascular events along with 1-year mortality in patients presenting with STEMI.
Conducted a retrospective cohort study of 645 consecutive STEMI patients undergoing primary percutaneous coronary intervention at a tertiary center in western Iran.
Stratified patients by tobacco exposure into never-smokers (n = 356), moderate smokers (<15 pack-years, n = 124), and heavy smokers (≥15 pack-years, n = 165).
Evaluated 1-year all-cause mortality and 365-day composite MACE using unadjusted and multivariable-adjusted Cox proportional hazards regression models.
After full multivariable adjustment, associations became non-significant for both 1-year mortality (HR: 0.92, 95% CI: 0.28–3.02) and MACE (HR: 1.51, 95% CI: 0.81–2.81).

Study Design

Type

Cohort (n=645)

Multicenter

No

Structured PICO

Does smoking status and cumulative exposure influence 1-year mortality and MACE in STEMI patients undergoing contemporary treatment?

P

Population

645 adults with STEMI presenting within 12 hours of symptom onset, free of prior MI or cardiogenic shock, followed for 1 year.

E

Exposure

Moderate smoking (<15 pack-years) or heavy smoking (≥15 pack-years)

C

Comparator

Never-smokers (individuals who had never smoked cigarettes)

O

Outcome

All-cause 1-year mortality followed for 12 months post-STEMI diagnosishard clinical

Main Result

Hazard Ratio: 0.92 (95% CI 0.28–3.02)

Absolute Event Rate: 6.06% vs 13.2%

p-value: p=0.896

Limitations

Prehospital deaths were not captured, potentially introducing survival bias.
Smoking exposure was based on self-report without biochemical validation (e.g., cotinine levels), risking recall bias and misclassification.
Unable to account for tobacco type, cessation duration, secondhand smoke, or use of other substances like opium or alcohol.
Single-center retrospective design with potential residual confounding and limited statistical power for subgroups.
Prehospital deaths were not captured, potentially underestimating true short-term mortality and introducing survival bias.
Smoking exposure was based on self-report without biochemical validation (e.g., cotinine levels), subject to recall bias.
Inability to account for tobacco type, duration of cessation, secondhand smoke, or other substances like opium and alcohol.
Single-center retrospective design limits generalizability and cannot fully exclude residual confounding.
Sample size (n=645) may limit statistical power for subtle subgroup effects, particularly in females.

Implication

The observed 'smoker's paradox' in STEMI patients is driven entirely by confounding factors such as younger age and fewer comorbidities, and disappears after multivariable adjustment.

Abstract

BACKGROUND: ST-elevation myocardial infarction (STEMI) remains a major cause of mortality worldwide. Whether smoking status and cumulative exposure influence prognosis in the contemporary era of timely reperfusion and intensive secondary prevention remains uncertain, particularly in populations with very high smoking rates. This study aimed to evaluate the association between smoking status and major adverse cardiovascular events (MACE) among patients with STEMI in western Iran. METHODS: A retrospective cohort study was conducted involving 645 consecutive patients with STEMI at a tertiary center in Western Iran. Patients were stratified by smoking status: never-smokers (n = 356), moderate smokers (<15 pack-years, n = 124), and heavy smokers (≥15 pack-years, n = 165). Outcomes included 1-year all-cause mortality and MACE over 365 days. Cox regression models adjusted for confounders were used to estimate hazard ratio with 95% confidence intervals (HR, 95% CI). RESULTS: In crude analyses, heavy smokers had lower 1-year mortality (HR = 0.44, 95% CI: 0.22-0.87) and MACE (HR = 0.60, 95% CI: 0.40-0.91) compared to never-smokers. After full adjustment, these associations became non-significant (mortality HR = 0.92, 95% CI: 0.28-3.02; MACE HR = 1.51, 95% CI: 0.81-2.81). Never-smokers were older, more likely female, and had higher comorbidity rates, explaining crude differences. Socioeconomic factors, particularly education, influenced outcomes. CONCLUSION: The smoker's paradox is driven by confounders, not a protective effect of smoking. Smoking cessation and addressing socioeconomic disparities are critical for improving STEMI outcomes in high-risk populations.

Discussion

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Cite This Study

Janjani et al. (2026) conducted a cohort in ST-elevation myocardial infarction (STEMI) (n=645). Heavy smoking (≥15 pack-years) vs. Never-smokers was evaluated on All-cause 1-year mortality (HR 0.92, 95% CI 0.28-3.02, p=0.896). After adjusting for confounding factors, heavy smoking (≥15 pack-years) was not associated with a reduced risk of 1-year mortality compared to never smoking in patients with STEMI (HR 0.92).

synapsesocial.com/papers/6ad0fcc53afa093ea9ad0038 https://doi.org/10.48305/arya.2026.45612.3094

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Impact of Smoking Status on Major Adverse Cardiovascular Events in STEMI Patients: A Retrospective Cohort Study in Western Iran.

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Impact of Smoking Status on Major Adverse Cardiovascular Events in STEMI Patients: A Retrospective Cohort Study in Western Iran.

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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