Aims: Cigarette smoking is a well-established risk factor for cardiovascular disease yet several studies have shown lower mortality after acute coronary syndromes in smokers compared with non-smokers, the so called 'smoker's paradox'. This study aimed to ascertain the relationship between smoking and clinical outcomes in patients hospitalized with heart failure (HF).
Methods and results: OPTIMIZE-HF (Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients with Heart Failure) collected data on 48 612 patients from 259 hospitals. Characteristics, treatments, and outcomes were compared for current/recent smokers vs. those without current/recent smoking, and multivariable regression analyses with adjustment for hospital clustering were performed. There were 7743 (15.9%) smokers, 39 126 (80.5%) non-smokers, and 1743 (3.6%) missing. Smokers were younger, had similar renal function, but lower ejection fraction. The risk of in-hospital mortality was less in smokers (2.3 vs. 3.9%, P < 0.001). After extensive covariate adjustment, smokers still had lower in-hospital mortality risk OR (odds ratio) 0.70, 95% CI (confidence interval) 0.56-0.88, P = 0.002. Post-discharge, smokers (n = 998) had similar mortality risk (6.7 vs. 8.4%, P = 0.29) compared with those without current/recent smoking.
Conclusion: Smokers hospitalized with HF had lower risk adjusted in-hospital mortality and similar early post-discharge mortality compared with non-smokers. The residual association of smoking and better prognosis, the 'smoker's paradox', was not fully explained by measured covariates.
Trial registration: ClinicalTrials.gov NCT00344513.