Smoking is a major risk factor for premature atherosclerosis, myocardial infarction (MI), heart failure (HF), and sudden cardiac death. Studies suggest that smokers lose at least a decade of life expectancy compared to non-smokers. Despite these well-documented risks, the short-term mortality rates following acute coronary syndromes (ACSs) or related HF are lower in current smokers than non-smokers, a phenomenon known as the smoker's paradox. This study aimed to examine the influence of smoking on in-hospital outcomes for patients diagnosed with aortic stenosis (AS) in the United States and ascertain the presence of the smoker's paradox in this patient population.

In this study, we utilized the National Inpatient Sample (NIS) for the year of 2020 to identify all patients who were admitted for a principal diagnosis of aortic stenosis (AS). Subsequently, we isolated those patients with an ICD-10 code indicating smoking or tobacco use. To examine associations, both logistic and linear regression analyses were employed while adjusting for potential confounding factors. Our findings were considered significant if the 2-tailed p-value was 0.05 or lower.

In 2020, there were 102,615 hospitalizations with a principal diagnosis of aortic stenosis, 41,689 (40.6%) of these cases involved patients with a secondary diagnosis of smoking history or use. After accounting for factors such as age, race, gender, hospital bed size, location, teaching status, insurance coverage, income level, and Elixhauser comorbidities, we found that patients who smoked and had AS demonstrated a lower rate of in-hospital mortality (aOR 0.64, 95% CI 0.51 – 0.81), mechanical ventilation (aOR 0.77, 95% CI 0.67- 0.88), vasopressor initiation (aOR 0.79, 95% CI 0.64- 0.95), mechanical circulatory support (aOR 0.56, 95% CI 0.34-0.91), and hemodialysis initiation (aOR 0.56, 95% CI 0.47-0.67) when compared to non-smoking patients with AS (Figure 1).

Our study demonstrated that patients with a primary diagnosis of aortic stenosis (AS) and a history of smoking or tobacco use had significantly lower odds of in-hospital mortality, mechanical ventilation, vasopressor use, mechanical circulatory support, and hemodialysis initiation compared to their non-smoking counterparts with AS. To comprehensively understand the smoker's paradox and its influence on clinical outcomes for patients hospitalized with AS, it is crucial to carry out larger, methodologically rigorous investigations. Such studies will aid in revealing the underlying mechanisms and reasons behind the persistence of this paradox, despite its apparent contradiction, ultimately enhancing our understanding and informing more effective patient care strategies.