After an acute ischemic stroke, persistent smoking increased the risk for cardiovascular (CV) events and mortality compared with never smoking, according to study findings published in the journal Stroke.
Previous studies have robustly linked cigarette smoking at the time of stroke with increased risk for major CV events; however, little is known about specific risks of persistent smoking after ischemic stroke.
Researchers from the Medical University of South Carolina performed this post-hoc analysis using data from the Small Subcortical Strokes (SPS3; Clinical Trials.gov Identifier: NCT00059306) trial, which was a randomized, multicenter trial conducted at 82 centers in the Americas and Spain between 2003 and 2012.
In this analysis, smoking status from month 3 after ischemic stroke was related with CV outcomes and mortality through an average follow-up of 38.8-42.7 months. Major adverse CV events (MACE) were defined as all-cause mortality, ischemic or hemorrhagic stroke, and myocardial infarction.
The study population comprised 1,152 never smokers, 1,152 prior smokers, and 570 current smokers at the time of ischemic stroke. Among the current smokers, 162 had quit by 3 months after ischemic stroke and 408 were persistent smokers.
The patients were mean age, 57.8-64.4 years; 22.8%-53.0% were women; 51.8%-64.2% were White; and 48.4%-52.7% were randomly assigned to receive an intensive blood pressure intervention. In general, the current smokers were younger than the past or never smokers, more women were never smokers than current or former smokers, and more of the current smokers were White than the former or never smokers (all, P <.001).
The former smokers had an average 24.0-year smoking history, which was shorter than the current smokers (mean range, 32.1-35.6 years; P <.001). Among the current smokers, the proportion of persistent smokers decreased throughout follow-up, from 71.6% at 3 months, to 68.3%, 67.3%, and 66.0% at 6, 12, and 18 months, respectively. However, a proportion of patients who quit smoking by 3 months had resumed smoking by 6 (14.2%) or 12 (20.4%) months.
Overall, the primary outcome of MACE occurred among 14.2% of the never smokers, 16.2% of the former smokers, 12.4% of the current smokers who quit by 3 months, and 18.4% of the persistent smokers.
Compared with never smokers, persistent smoking was associated with increased risk for MACE (adjusted hazard ratio [aHR], 1.56; 95% CI, 1.16-2.09; P =.009).
Stratified by MACE events, compared with never smokers, no increased risk for stroke or myocardial infarction was observed during follow-up, however, the persistent smokers were at increased risk for mortality (aHR, 2.00; 95% CI, 1.28-3.13; P =.006).
In a subgroup analysis, age was found to have a significant interaction for the primary outcome (P <.001), in which increased risk for MACE among persistent smokers compared with never smokers was only significant among patients younger than age 60 (aHR, 1.76; 95% CI, 1.14-2.74) but not for those age 60 or older (aHR, 1.15; 95% CI, 0.76-1.73).
Researchers acknowledged, “[W]e demonstrated an association between persistent smoking after stroke and higher risk of composite outcome of death, stroke, and myocardial infarction.”
The limitations of this analysis included the modest sample size of patients who quit smoking after ischemic stroke and the fact that smoking status changed among many patients at every 3-month follow-up.
“Persistent smoking compared to never smoking after lacunar stroke was associated with a significant increase in the risk of major cardiovascular events and death,” the researchers wrote. “The overall rate of smoking cessation after ischemic stroke was low, highlighting the need for more targeted and effective smoking cessation strategies.”
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Anadani M, Turan TN, Yaghi S, et al. Change in smoking behavior and outcome after ischemic stroke: post-hoc analysis of the SPS3 trial. Stroke. Published online March 6, 2023. doi:10.1161/STROKEAHA.121.038202