Doi SA, Islam N, Sulaiman K, et al. - Given that smoker's paradox has been seen with many vascular disorders, however, for patients with acute heart failure (HF), there exists limited data, and therefore, researchers used data from a large multicenter registry and determined the influences of smoking in patients with acute HF, with the goal to investigate whether the design and analytic approach could explain the smoker's paradox in acute HF mortality. This study included a total of 5,005 patients hospitalized with acute HF. Of these, current smokers were 1,103 (22%). Findings revealed significantly lower in-hospital mortality rates in current smokers prior to and more so following covariate adjustment. Experts concluded that residual confounding possibly causes the smoker's paradox as covariate adjustment may not resolve this if there are many competing prognostic confounders. A seemingly preferable choice in this situation is propensity score methods for covariate balancing.