Smoking Cessation Halves MACE Risk, Reduction Offers Little Protection

Quitting smoking after a diagnosis of stable coronary artery disease (CAD) was linked to a nearly 50% reduction in the risk of major cardiovascular (CV) events, although cutting down smoking demonstrated little impact on CV risk, according to new research.¹

These 5-year follow-up data, presented at the European Society of Cardiology (ESC) Congress 2024, were obtained from more than 32,000 patients in the international CLARIFY registry, assessing the impact of smoking status on cardiovascular events in CAD.

“I like to tell my patients that it is never too soon or too late to stop smoking, though the sooner a patient stops, the better to lower cardiovascular risk,” said Professor Jules Mesnier, assistant clinical head, of cardiology, Hospital Bichat-Claude Bernard.² “And it is not enough to reduce smoking.”

Patients were included for analysis after an average of 6.5 years after CAD diagnosis.¹ At the point of inclusion, 13,366 patients (41.3%) had never smoked, 14,972 (46.2%) were former smokers, and 4039 (12.5%) were current smokers.

Notably, approximately 73% of former smokers, who smoked at the time of CAD diagnosis, discontinued smoking within the following year, while only 27% of patients quit in the following years.

The occurrence of a major adverse cardiovascular event (MACE) was determined in the analysis, defined as cardiovascular death or myocardial infarction during the 5-year follow-up period.

Upon analysis, those who quit smoking after CAD diagnosis led to a significant improvement in cardiovascular outcomes, irrespective of the quitting period. These data showed a 44% reduction in MACE risk (adjusted hazard ratio [aHR], 0.56; 95% CI, 0.42–0.76; P <.001).

For smokers who cut down their smoking, MACE risk did not exhibit significant alterations compared with those who did not change smoking habits (aHR, 0.96; 95% CI, 0.74–1.26; P = .78). Each additional year of active smoking increased MACE risk after CAD diagnosis by approximately 8% (aHR, 1.08; 95% CI, 1.04–1.12 per year).

Smokers who quit smoking achieved a rapid significant reduction in MACE risk, compared with current smokers. However, these individuals were unable to reach the CV risk level of patients who never smoked, even after years of smoking cessation.

“Interestingly, the first year after diagnosis was the crucial window for quitting,” Mesnier said.² At the time of diagnosis, we should emphasize the importance of quitting and support patients in this challenge.”

Smoking is a recognized risk factor for recurrent CV events in CAD, but these data indicate that smoking habits in this population can vary widely.¹ Overall, Mesnier and colleagues suggested these new findings emphasize the urgent need for timely smoking cessation for patients with CAD.

“Short, clear messages are needed for smokers at every medical intervention highlighting the need to quit,” Mesnier added.² “Telling patients they can cut their risk of a subsequent major event or death by half – as we have shown here – is a powerful message.”

References

1. _{Mesnier J, Giovachini L, Danchin N, et al. Trajectories of Smoking Habits and Associated Outcomes in Patients with Stable Coronary Artery Disease. Presented at the European Society of Cardiology (ESC) Congress 2024. London, England. 30 August – 2 September, 2024.}
2. _{European Society of Cardiology (ESC). Quitting smoking nearly halves heart attack risk, cutting down does little. Published August 29, 2024. Accessed August 29, 2024.}
3. _{Visseren FLJ, Mach F, Smulders YM, et al. 2021 ESC Guidelines on cardiovascular disease prevention in clinical practice [published correction appears in Eur Heart J. 2022 Nov 7;43(42):4468. doi: 10.1093/eurheartj/ehac458]. Eur Heart J. 2021;42(34):3227-3337. doi:10.1093/eurheartj/ehab484}