Smoking and long-term risks for morbidity and mortality after coronary artery bypass grafting

Background

We explored the association between smoking and long-term risks of morbidity and mortality in patients who had undergone coronary artery bypass grafting (CABG).

Methods

This population-based registry study included 27,434 patients (mean age 67.9 years, 18.2 % women), divided into: never smokers (n = 8,593), former smokers (n = 14,666) and current smokers (n = 4,175), who underwent CABG between 2010 and 2020. Data were collected from the SWEDEHEART registry. Three other mandatory registers provided data on comorbidities, social factors and outcome variables. Adjusted Cox regression models were used to estimate mortality and morbidity. The median follow-up was 5 (0–11) years.

Results

Current smokers were younger and had a higher proportion of previous myocardial infarction, heart failure, chronic respiratory disease, depression and low education compared with never smokers. Compared with never smokers, current smokers had higher risk for a major adverse cardiovascular event (MACE) (adjusted hazard ratio (aHR) 1.52, 95 % confidence interval (CI) 1.39–1.66), all-cause mortality (aHR 1.91, (1.71–2.14)) and stroke (aHR 1.49, (1.27–1.74)) but not for myocardial infarction (aHR 1.07, (0.91–1.26)). Compared with former smokers, current smokers had an increased risk for MACE (aHR 1.38, (1.27–1.49)), all-cause mortality (aHR 1.53, (1.39–1.69)), stroke (aHR 1.36, (1.18–1.56)), but not for myocardial infarction (aHR 1.15, (1.00–1.34)).

Conclusions

There was a strong association between smoking and long-term risk for mortality and morbidity after CABG. The highest risks were observed in current smokers. The results emphasize the importance of motivating CABG patients to smoking cessation before considering CABG as a treatment option.