Abstract 18349: Cigarette Smoking Associated With Increased All-Cause Mortality In Individuals Across the Whole Spectrum of Coronary Atherosclerosis
Background: Data is limited on the prognostic impact of smoking on atherosclerotic imaging burden.The purpose of this study was to assess whether smoking remains an independent predictor of all cause mortality in the absence of, as well as across increasing, coronary artery calcium (CAC) burden in a long term follow—up.
Methods: The study cohort consisted of 44,052 (54±11 years, 54% males) asymptomatic individuals free of known coronary heart disease referred for electron beam computed tomography (EBT) for the assessment of subclinical atherosclerosis. Patients were followed for a mean of 5.6 (range 1–13 years). The primary endpoint for the study cohort was mortality from any cause.
Results: 14% (n=6020) of subjects were smokers. There were 901 deaths (2.05%) overall, with significantly lower (p < 0.0001) overall survival in cigarette smokers vs. non-smokers. The annualized mortality rate was 2.86 deaths per 1,000 person-years (95% confidence interval [CI] 2.64 - 3.09) for non-smokers vs. 10.99 deaths per 1,000 person-years (95% CI: 9.63–12.30) among smokers. Compared to smokers with a CAC score of 0, the hazard ratios (95% CI) with increasing CAC scores (1–99, 100–399, and ≥400) were 2.03 (2.59, 1.68–3.99), 4.71 (3.06–7.26) and 8.76 (5.81–13.21). Among smokers who died, CAC>400 was noted in 37% participants at baseline as compared to 13% of smokers who survived (p<0.0001). CAC added significantly to prediction of all cause mortality beyond traditional risk factors among smokers (chi square= 47.80, p<0.0001). In the 19,898 individuals with CAC=0 at baseline, 13-year all-cause survival was 99.6% and 98.7% for non smokers and smokers, a small but significant difference (p<0.001). Smoking was associated with 3 fold higher risk of mortality (HR 3.62, 95% CI: 2.28–5.75) in this low risk group (CAC=0). The respective hazard ratio (95% CI) for all-cause mortality among those with CAC scores 1–100, 101–400 and >400 with smoking were 3.82 (2.82–5.22), 3.54 (2.57–4.89), and 2.71 (2.12–3.48).
Conclusion: A higher CAC score contributed significantly to predicting all cause mortality among smokers. Individuals with CAC=0 who smoke are at relatively increased risk of death.. Efforts should be made to encourage smoking cessation in those with and without CAC=0.
- © 2010 by American Heart Association, Inc.