Smoking Paradox in Stroke Survivors?: Uncovering the Truth by Interpreting 2 Sets of Data

Predicting 90-day prognosis for patients with stroke: a machine learning approach

Background

Stroke is a significant global health burden and ranks as the second leading cause of death worldwide.

Objective

This study aims to develop and evaluate a machine learning-based predictive tool for forecasting the 90-day prognosis of stroke patients after discharge as measured by the modified Rankin Score.

Methods

The study utilized data from a large national multiethnic stroke registry comprising 15,859 adult patients diagnosed with ischemic or hemorrhagic stroke. Of these, 7,452 patients satisfied the study's inclusion criteria. Feature selection was performed using the correlation and permutation importance methods. Six classifiers, including Random Forest (RF), Classification and Regression Tree, Linear Discriminant Analysis, Support Vector Machine, and k-Nearest Neighbors, were employed for prediction.

Results

The RF model demonstrated superior performance, achieving the highest accuracy (0.823) and excellent discrimination power (AUC 0.893). Notably, stroke type, hospital acquired infections, admission location, and hospital length of stay emerged as the top-ranked predictors.

Conclusion

The RF model shows promise in predicting stroke prognosis, enabling personalized care plans and enhanced preventive measures for stroke patients. Prospective validation is essential to assess its real-world clinical performance and ensure successful implementation across diverse healthcare settings.

Impact of smoking on outcomes following endovascular therapy for acute ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Smoking represents a leading risk factor for acute ischemic stroke (AIS). Previous literature has described a "smoking paradox", wherein smokers experience better outcomes following intravenous thrombolysis for AIS. It is unclear whether such a phenomenon exists in smokers undergoing endovascular therapy (EVT) for AIS. To assess outcomes in smokers following EVT for AIS, we conducted a systematic review and meta-analysis.

METHODS

Following the PRISMA guidelines, a systematic literature review of the English language literature was conducted using PubMed, Embase Web of Science, and Scopus. Outcomes of interest included 90-day modified Rankin Scale (mRS) 0-2, thrombolysis in cerebral infarction (TICI) score 2b-3, symptomatic intracranial hemorrhage (sICH), and mortality. We calculated mean difference (MD), pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CI).

RESULTS

Eight studies with 2633 patients comprised our analysis. On average, smokers were 10.14 years (MD  =  10.14, [95% CI  =  -14.49 to -5.79], P-value < 0.001) younger than non-smokers. Smokers achieved mRS 0-2 (OR =  1.82, [95% CI, 1.34-2.48], P-value < 0.001) and TICI 2b-3 (OR =  1.61, [95% CI, 1.19-2.19], P-value  =  0.002) at a higher rate than non-smokers. sICH rates were comparable between smokers and non-smokers (OR =  1.07, [95% CI, 0.62-1.85], P-value  =  0.81). Smokers had a lower rate of 90-day mortality than non-smokers (OR =  0.54, [95% CI, 0.41-0.71], P-value < 0.001).

CONCLUSIONS

In this meta-analysis of eight studies, we found that smokers with AIS undergoing EVT experienced better 90-day outcomes and higher rates of TICI 2b-3. This may be due to baseline differences between smokers and non-smokers, but future studies should explore alternative reasons that could explain this relationship between smoking and AIS treated with EVT.

Effect of Air Pollution Particulate Matter on Ischemic and Hemorrhagic Stroke: A Scoping Review

Air pollution particulate matter (PM) exposure has been established as a risk factor for stroke. However, few studies have investigated the effects of PM exposure on stroke subtypes (ischemic and hemorrhagic stroke). Ischemic (IS) and hemorrhagic strokes (HS) involve distinctive pathophysiological pathways and may be differentially influenced by PM exposure. This review aims to characterize the effects of PM exposure on ischemic and hemorrhagic strokes. It also identifies subpopulations that may be uniquely vulnerable to PM toxicity. Pubmed was queried from 2000 to 2023 to identify clinical and epidemiological studies examining the association between PM exposure and stroke subtypes (ischemic and hemorrhagic stroke). Inclusion criteria were: 1) articles written in English 2) clinical and epidemiological studies 3) studies with a clear definition of stroke, IS, HS, and air pollution 4) studies reporting the effects of PM and 5) studies that included distinct analyses per stroke subtype. Two independent reviewers screened the literature for applicable studies. A total of 50 articles were included in this review. Overall, PM exposure increases ischemic stroke risk in both lightly and heavily polluted countries. The association between PM exposure and hemorrhagic stroke is variable and may be influenced by a country's ambient air pollution levels. A stronger association between PM exposure and stroke is demonstrated in older individuals and those with pre-existing diabetes. There is no clear effect of sex or hypertension on PM-associated stroke risk. Current literature suggests PM exposure increases ischemic stroke risk, with an unclear effect on hemorrhagic stroke risk. Older patients and those with pre-existing diabetes may be the most vulnerable to PM toxicity. Future investigations are needed to characterize the influence of sex and hypertension on PM-associated stroke risk.

Patient and hospital characteristics associated with do-not-resuscitate/do-not-intubate orders: a cross-sectional study based on the Taiwan stroke registry

BACKGROUND

Previous studies of do-not-resuscitate (DNR) or do-not-intubate (DNI) orders in stroke patients have primarily been conducted in North America or Europe. However, characteristics associated with DNR/DNI orders in stroke patients in Asia have not been reported.

METHODS

Based on the Taiwan Stroke Registry, this nationwide cross-sectional study enrolled hospitalized stroke patients from 64 hospitals between 2006 and 2020. We identified characteristics associated with DNR/DNI orders using a two-level random effects model.

RESULTS

Among the 114,825 patients, 5531 (4.82%) had DNR/DNI orders. Patients with acute ischemic stroke (AIS) had the highest likelihood of having DNR/DNI orders (adjusted odds ratio [aOR] 1.76, 95% confidence interval [CI] 1.61-1.93), followed by patients with intracerebral hemorrhage (ICH), and patients with subarachnoid hemorrhage (SAH) had the lowest likelihood (aOR 0.53, 95% CI 0.43-0.66). From 2006 to 2020, DNR/DNI orders increased in all three types of stroke. In patients with AIS, women were significantly more likely to have DNR/DNI orders (aOR 1.23, 95% CI 1.15-1.32), while patients who received intravenous alteplase had a lower likelihood (aOR 0.74, 95% CI 0.65-0.84). Patients with AIS who were cared for by religious hospitals (aOR 0.55, 95% CI 0.35-0.87) and patients with SAH who were cared for by medical centers (aOR 0.40, 95% CI 0.17-0.96) were significantly less likely to have DNR/DNI orders.

CONCLUSIONS

In Taiwan, DNR/DNI orders increased in stroke patients between 2006 and 2020. Hospital characteristics were found to play a significant role in the use of DNR/DNI orders.

From Admission to Discharge: Predicting National Institutes of Health Stroke Scale Progression in Stroke Patients Using Biomarkers and Explainable Machine Learning

As a result of social progress and improved living conditions, which have contributed to a prolonged life expectancy, the prevalence of strokes has increased and has become a significant phenomenon. Despite the available stroke treatment options, patients frequently suffer from significant disability after a stroke. Initial stroke severity is a significant predictor of functional dependence and mortality following an acute stroke. The current study aims to collect and analyze data from the hyperacute and acute phases of stroke, as well as from the medical history of the patients, in order to develop an explainable machine learning model for predicting stroke-related neurological deficits at discharge, as measured by the National Institutes of Health Stroke Scale (NIHSS). More specifically, we approached the data as a binary task problem: improvement of NIHSS progression vs. worsening of NIHSS progression at discharge, using baseline data within the first 72 h. For feature selection, a genetic algorithm was applied. Using various classifiers, we found that the best scores were achieved from the Random Forest (RF) classifier at the 15 most informative biomarkers and parameters for the binary task of the prediction of NIHSS score progression. RF achieved 91.13% accuracy, 91.13% recall, 90.89% precision, 91.00% f1-score, 8.87% FNrate and 4.59% FPrate. Those biomarkers are: age, gender, NIHSS upon admission, intubation, history of hypertension and smoking, the initial diagnosis of hypertension, diabetes, dyslipidemia and atrial fibrillation, high-density lipoprotein (HDL) levels, stroke localization, systolic blood pressure levels, as well as erythrocyte sedimentation rate (ESR) levels upon admission and the onset of respiratory infection. The SHapley Additive exPlanations (SHAP) model interpreted the impact of the selected features on the model output. Our findings suggest that the aforementioned variables may play a significant role in determining stroke patients' NIHSS progression from the time of admission until their discharge.

Revisiting the Smoking Paradox in Acute Ischemic Stroke Patients: Findings From the Chinese Stroke Center Alliance Study

Background Smoking is a well-established risk factor for the development of acute ischemic stroke (AIS). However, the "smoker's paradox" suggests that it is associated with favorable clinical outcomes following stroke. We aimed to reevaluate the association between smoking and in-hospital outcomes in patients with AIS in contemporary practice. Methods and Results A total of 649 610 inpatients with AIS from 1476 participating hospitals in the Chinese Stroke Center Alliance were included. In-hospital outcomes measurement included all-cause mortality, discharge against medical advice, and complications. Multivariable logistic regression models adjusting for baseline characteristics, clinical profiles at presentation, and in-hospital management were used to evaluate the association between smoking and in-hospital outcomes. A propensity score-matched analysis was also conducted. Of these patients with AIS, 36.8% (n=238 912) were smokers. Smokers were younger, had fewer comorbidities, and had slightly lower rates of adverse in-hospital outcomes than nonsmokers (all-cause death or discharge against medical advice: 6.0% versus 6.1%; in-hospital complications: 14.5% versus 15.1%). Multivariable analysis revealed that smoking was associated with higher risk of adverse in-hospital outcomes (all-cause death or discharge against medical advice: odds ratio [OR], 1.05 [95% CI, 1.02-1.08]; P<0.001; complications: OR, 1.06 [95% CI, 1.04-1.08]; P<0.001). The excess risk of adverse in-hospital outcomes remained in smoking patients with AIS after propensity score-matching analysis (all-cause death or discharge against medical advice: OR, 1.04 [95% CI, 1.00-1.08]; P=0.034; complications: OR, 1.05 [95% CI, 1.03-1.08]; P<0.001). Conclusions Smoking was associated with increased risk of adverse in-hospital outcomes among patients with AIS in contemporary practice, reinforcing the importance of smoking cessation in patients with AIS.

The 2023 Taiwan Stroke Society Guidelines for the management of patients with intracranial atherosclerotic disease

Intracranial atherosclerotic disease (ICAD) is a major cause of ischemic stroke, especially in Asian populations, which has a high risk of recurrent stroke and cardiovascular comorbidities. The present guidelines aim to provide updated evidence-based recommendations for diagnosis and management of patients with ICAD. Taiwan Stroke Society guideline consensus group developed recommendations for management of patients with ICAD via consensus meetings based on updated evidences. Each proposed class of recommendation and level of evidence was approved by all members of the group. The guidelines cover six topics, including (1) epidemiology and diagnostic evaluation of ICAD, (2) nonpharmacological management of ICAD, (3) medical therapy for symptomatic ICAD, (4) endovascular thrombectomy and rescue therapy for acute ischemic stroke with underlying ICAD, (5) endovascular interventional therapy for postacute symptomatic intracranial arterial stenosis, and (6) surgical treatment of chronic symptomatic intracranial arterial stenosis. Intensive medical treatment including antiplatelet therapy, risk factor control, and life style modification are essential for patients with ICAD.

Construction of a Nomogram Prediction Model for Prognosis in Patients with Large Artery Occlusion-Acute Ischemic Stroke

BACKGROUND

Patients with large artery occlusion-acute ischemic stroke (LAO-AIS) can experience adverse outcomes, such as brain herniation due to complications. This study aimed to construct a nomogram prediction model for prognosis in patients with LAO-AIS in order to maximize the benefits for clinical patients.

METHODS

Retrospective analysis of 243 patients with LAO-AIS from January 2019 to January 2022 with medical history data and blood examination at admission. Univariate and multivariate analyses were conducted through binary logistic regression equation analysis, and a nomogram prediction model was constructed.

RESULTS

Results of this study showed that hyperlipidemia (odds ratio [OR] = 2.849, 95% confidence interval [CI] = 1.100-7.375, P = 0.031), right cerebral infarction (OR = 2.144, 95% CI = 1.106-4.156, P = 0.024), D-Dimer>500 ng/mL (OR = 2.891, 95% CI = 1.398-5.980, P = 0.004), and neutrophil-lymphocyte ratio >7.8 (OR = 2.149, 95% CI = 1.093-4.225, P = 0.027) were independent risk factors for poor early prognosis in patients with LAO-AIS. In addition, hypertension (OR = 1.947, 95% CI = 1.114-3.405, P = 0.019), hyperlipidemia (OR = 2.594, 95% CI = 1.281-5.252, P = 0.008), smoking (OR = 2.414, 95% CI = 1.368-4.261, P = 0.002), D-dimer>500 ng/mL (OR = 3.170, 95% CI = 1.533-6.553, P = 0.002), and neutrophil-lymphocyte ratio >7.8 (OR = 2.144, 95% CI = 1.231-3.735, P = 0.007) were independent risk factors for poor long-term prognosis. The early prognosis nomogram receiver operating characteristic curve area under the curve value was 0.688 for the training set and 0.805 for the validation set, which was highly differentiated. The mean error was 0.025 for the training set calibration curve and 0.016 for the validation set calibration curve. Both the training and validation set decision curve analyses indicated that the clinical benefit of the nomogram was significant. The long-term prognosis nomogram receiver operating characteristic curve area under the curve values was 0.697 for the training set and 0.735 for the validation set, showing high differentiation. The mean error was 0.041 for the training set calibration curve and 0.021 for the validation set calibration curve. Both of the training and validation set decision curve analyses demonstrated a substantial clinical benefit of the nomogram.

CONCLUSIONS

The nomogram prediction model based on admission history data and blood examination are easy-to-use tools that provide an accurate individualized prediction for patients with LAO-AIS and can assist in early clinical decisions and in obtaining an early prognosis.

Effects of smoking on the prognosis of anterior circulation acute ischemic stroke with intravenous thrombolysis

OBJECTIVE

This is a single-center retrospective analysis of the clinical data of 516 patients with acute ischemic stroke who underwent intravenous thrombolysis. This study was conducted to compare the therapeutic efficacy of smokers and non-smokers.

METHODS

Univariate analysis was used to analyze and compare the clinical data of smokers and non-smokers. Multivariate analysis was used to assess risk factors affecting the 90-day modified Rankin Scale (mRS) score.

RESULTS

Among the 516 patients, 235 (45.5 %) were smokers. Univariate analysis showed that smokers have a better 90-day prognosis and a lower 90-day mRS score than non-smokers. Multivariate logistic regression analysis showed that smoking is not a protective factor affecting prognosis, while baseline National Institutes of Health Stroke Scale (NIHSS) score was an independent risk factor affecting the 90-day functional outcome. Subgroup analysis did not determine a relationship between the 90-day mRS score and the smoking intensity and duration.

CONCLUSION

Smoking was not associated with a good 90-day prognosis after intravenous thrombolysis (IVT) treatment. The good clinical outcome of smokers in univariate analysis was bound up with their baseline characteristics. Baseline NIHSS score was the independent risk factor that affected the 90-day outcome of AIS patients undergoing IVT.

The Smoking Paradox in Stroke Patients Under Reperfusion Treatment Is Associated With Endothelial Dysfunction

Objective

This study aimed to explore the association between smoking habit and the serum levels of soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK), in relation with the functional outcome of patients with acute ischemic stroke undergoing reperfusion treatment.

Methods

Observational and retrospective study of a series of patients with acute ischemic stroke subjected to reperfusion treatments. Clinical, analytical, and neuroimaging parameters were analyzed. The main endpoint was the functional outcome at 3 months, measured by the modified Ranking Scale (mRS). Logistic regression models were used to analyze the association between smoking and sTWEAK levels with functional outcome and leukoaraiosis.

Results

The results showed that smoking habit was associated with a good functional outcome at 3 months in patients with stroke (OR: 3.52; 95% CI: 1.03–11.9; p = 0.044). However, this independent association was lost after adjusting by sTWEAK levels (OR 1.73; 95% CI: 0.86–13.28; p = 0.116). sTWEAK levels were significantly lower in smoker patients [4015.5 (973.66–7921.83) pg/ml vs. 5,628 (2,848–10,202) pg/ml, p < 0.0001], while sTWEAK levels were significantly higher in patients with poor functional outcomes at 3 months [10,284 (7,388–13.247) pg/ml vs. 3,405 (2,329–6,629) pg/ml, p < 0.0001].

Conclusion

The decrease in sTWEAK levels was associated with a good functional outcome in smoker patients with stroke undergoing reperfusion therapy.

Predictors of mortality in acute ischemic stroke treated with endovascular thrombectomy despite successful reperfusion: subgroup analysis of a multicentre randomised clinical trial

OBJECTIVES

We sought to determine the predictors of 90-day mortality despite successful reperfusion.

DESIGN

Subgroup analysis of a multicentre randomised clinical trial (ClinicalTrials.gov Identifier: NCT03469206).

SETTING

This study used data from the Direct Intra-arterial thrombectomy in order to Revascularize AIS patients with large vessel occlusion Efficiently in Chinese Tertiary hospitals: a Multicenter randomized clinical Trial (DIRECT-MT).

PARTICIPANTS

622 patients enrolled in DIRECT-MT.

RESULTS

Overall successful reperfusion rate was 82.0% (510/622), and 18.5% (115/622) of patients died within 90 days. Univariate analysis identified increased risks of mortality for age ≥70 years, history of diabetes mellitus, National Institutes of Health Stroke Scale (NIHSS) score on admission ≥17, NIHSS score after thrombectomy (24±6 hours) ≥11, Alberta Stroke Program Early Computed Tomography Score (ASPECTS) <9, glucose level at hospital arrival ≥130 mg/dL, location of internal carotid artery occlusion, embolisation into a new territory, symptomatic intracranial haemorrhage (ICH) and a decreased risk of mortality for smoking. In multivariable analysis, smoking (OR 0.38; 95% CI 0.17 to 0.83; p=0.015), NIHSS score on admission ≥17 (OR 3.14; 95% CI 1.77 to 5.55; p<0.001), glucose level at hospital arrival ≥130 mg/dL (OR 2.54; 95% CI 1.51 to 4.27; p<0.001), symptomatic ICH (OR 11.70; 95% CI 4.74 to 28.89; p<0.001) and NIHSS score after thrombectomy (24±6 hours) ≥11 (OR 12.04; 95% CI 5.09 to 28.46; p<0.001) were significant independent predictors of 90-day mortality.

CONCLUSIONS

Symptomatic ICH and high post-thrombectomy NIHSS score are strong predictor of 90-day mortality in acute ischaemic stroke treated with mechanical thrombectomy despite successful reperfusion, as well as high NIHSS score and high glucose level at hospital arrival. However, further studies need to be performed to confirm the association between smoking and mortality.

Acupuncture May Decrease the Incidence of Post-stroke Dementia: A Taiwan Nationwide Retrospective Cohort Study

Background: Post-stroke dementia may affect up to one-third of stroke survivors. Acupuncture as a complementary treatment for stroke has been shown to be beneficial for subsequent post-stroke rehabilitation. The purpose of this retrospective cohort study was to investigate the potential effect of acupuncture to protect stroke patients from dementia.

Methods: We included 9,547 patients receiving ambulatory or hospital care for stroke and 9.547 non-stroke patients; patients were matched for sex, age, and Charlson Comorbidity Index. Each individual was traced for the subsequent development of dementia. Two thousand four hundred and forty-nine stroke patients received acupuncture treatment and 7,098 residue stroke patients without acupuncture treatment served as control groups. This is a 3-year follow-up cohorts study: the incidence and adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of post- stroke dementia in the Cox proportional hazard regression.

Results: During the 3-year follow-up, 1,403 patients with stroke (14.70%) and 427 patients without stroke (4.47%) developed dementia. The adjusted HRs of development of dementia among stroke patients were 3.64-times (range, 3.27–4.06), and the incidence of dementia was higher in male. Stroke patients receiving acupuncture treatment had a lower probability of dementia than those without acupuncture during the follow-up period, the adjusted HRs was 0.49 (95% CI, 0.42–0.58; p < 0.001).

Conclusions: The association between stroke and dementia existed in both sexes, more prominent in male. Patients with stroke receiving acupuncture treatments showed decreased risk of dementia. Care must be taken evaluating these results because this study was limited to lack of information regarding lifestyles, stroke severities, and acupuncture methods that were used in treatments.

Smoking influences outcome in patients who had thrombolysed ischaemic stroke: the ENCHANTED study

Background and purpose

As studies vary in defining the prognostic significance of smoking in acute ischaemic stroke (AIS), we aimed to determine the relation of smoking and key outcomes in patient participants who had thrombolysed AIS of the international quasi-factorial randomised Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED).

Methods

Post-hoc analyses of ENCHANTED, an international quasi-factorial randomised evaluation of intravenous alteplase-dose comparison and levels of blood pressure control in patients who had thrombolysed AIS. Multivariable logistic regression models with inverse probability of treatment weighting (IPTW) propensity scores were used to determine associations of self-reported smoking status and clinical outcomes, according to 90-day modified Rankin Scale (mRS) scores and symptomatic intracerebral haemorrhage (sICH).

Results

Of 4540 patients who had an AIS, there were 1008 (22.2%) current smokers who were younger and predominantly male, with more comorbidities of hypertension, coronary artery disease, atrial fibrillation and diabetes mellitus, and greater baseline neurological impairment, compared with non-smokers. In univariate analysis, current smokers had a higher likelihood of a favourable shift in mRS scores (OR 0.88, 95% CI 0.77 to 0.99; p=0.038) but this association reversed in a fully adjusted model with IPTW (adjusted OR 1.15, 95% CI 1.04 to 1.28; p=0.009). A similar trend was also apparent for dichotomised poor outcome (mRS scores 2–6: OR 1.18, 95% CI 1.05 to 1.33; p=0.007), but not with the risk of sICH across standard criteria.

Conclusion

Smoking predicts poor functional recovery in patients who had thrombolysed AIS.

Trial registration number

NCT01422616.

A Meta-Analysis of Prognostic Factors in Patients with Posterior Circulation Stroke after Mechanical Thrombectomy

BACKGROUND

Posterior circulation stroke is characterized by poor prognosis because its optimal thrombolysis "time window" is always missed. After mechanical thrombectomy (MT), the recanalization rate of posterior circulation obstruction is significantly increased, but prognosis remains poor. To best manage patients, prognostic factors are needed to inform MT triaging after posterior circulation stroke.

METHODS

A systematic literature search was done for the period through April 2020. Studies included those with posterior circulation stroke cases that underwent MT. The primary outcome measure in this study was the modified Rankin Scale on day 90.

RESULTS

No outcome differences were found in gender, atrial fibrillation, smoking, and coronary artery disease (OR = 1.07, 95% CI: 0.90-1.28; OR = 1.02, 95% CI: 0.82-1.26; OR = 1.26, 95% CI: 0.94-1.68; and OR = 0.84, 95% CI: 0.58-1.22, respectively). Hypertension, diabetes mellitus, and previous stroke correlated with poorer prognosis (OR = 0.61, 95% CI: 0.48-0.77; OR = 0.60, 95% CI: 0.50-0.73; and OR = 0.74, 95% CI: 0.55-0.99, respectively). However, hyperlipidemia correlated with better prognosis (OR = 1.28, 95% CI: 1.04-1.58).

CONCLUSION

Our analysis indicates that hypertension, diabetes mellitus, or previous stroke correlate with poorer outcomes. Intriguingly, hyperlipidemia correlates with better prognosis. These factors may help inform triage decisions when considering MT for posterior circulation stroke patients. However, large, multicenter, randomized controlled trials are needed to validate these observations.