Chronic bronchitis and acute infections as new risk factors for ischemic stroke and the lack of protection offered by the influenza vaccination

Association of cataract surgery with stroke among older adults in the United States

BACKGROUND/OBJECTIVES

Cataract surgery, one of the most frequent conducted surgeries around the world, is associated with cardiovascular diseases. We aim to determine the association of cataract surgery and the risk of stroke.

METHODS

Adults aged over 65 years old in the National Health and Aging Trends Study were followed 7 years annually. There were 6700 stroke-free participants included at baseline survey. These participants were divided into two groups based on past history of cataract surgery. Demographics and multiple comorbidities were compared between the two groups. We identified newly developed cases of stroke over a 7-year period and performed survival analysis. Cox regression was further performed to yield adjusted hazard ratios.

RESULTS

Among 6700 elderly participants, 2803 of them had a history of cataract surgery while 3897 of them had not. Over the 7-year follow-up period, the cumulative stroke-free survival rate among the cataract surgery group and the control group were 84.4% versus 88.6% (p < 0.0001, log-rank test). Compared with the control group, elderly with a history of cataract surgery had a higher risk of developing stroke (adjusted HR 1.36, 95% CI 1.03 to 1.79, p = 0.026) after adjusting for multiple covariates. Other significant predictors included age ≥80 years old, having comorbidities with heart disease, lung disease, and dementia. Contrarily, protective factors for further stroke development included higher education and more frequent outdoor activities.

CONCLUSIONS

Our findings suggest that patients with a history of cataract surgery had a 1.36-fold increased risk of future stroke development.

Evaluating the impact of influenza vaccine on preventing stroke hospitalization and death in Chinese elderly hypertensive patients: A retrospective cohort study

BACKGROUND

The effect of influenza vaccination on stroke remains controversial, particularly given the paucity of studies conducted in mainland China.

METHODS

Using a comprehensive database obtained from the Regional Health Information Platform, we conducted a 7-month retrospective cohort analysis of 457,887 elderly individuals residing in an eastern Chinese city. Using multivariate competing risks regression analysis, we derived subdistribution hazard ratios (sHRs) along with the corresponding 95 % confidence intervals (CIs).

RESULTS

There was no significant difference in the proportion of hospitalizations for stroke between those who received the influenza vaccine and those who did not (7.50 per 1000 vs. 8.12 per 1000; adjusted sHR: 0.96, 95 % CI: 0.90-1.02). However, a pronounced reduction in stroke-related mortality was observed among vaccinated individuals, with a rate of 0.18 ‰ compared with 0.54 ‰ among the unvaccinated (adjusted sHR: 0.47, 95 % CI: 0.33-0.69).

CONCLUSION

This study highlights the substantial role of influenza vaccination in reducing the risk of stroke-related mortality in elderly hypertensive patients. Therefore, efforts to increase influenza vaccination rates in this population are strongly encouraged.

Aetiology of Acute Respiratory Insufficiency in Patients With Ischaemic Stroke Studied by Chest CT Scan

BACKGROUND

Acute respiratory insufficiency (ARI) is considered a serious life-threatening complication after ischaemic stroke. The aim of this study was to identify the most common aetiologies of ARI after stroke and their association with patients' outcome.

METHODS

This retrospective study was conducted at the University Hospital Bonn, involving patients with acute ischaemic stroke who underwent chest CT scans for ARI between 2017 and 2022. We collected clinical and demographic data, laboratory parameters, vital signs, as well as outcome parameters. CT scans were reviewed by a radiologist. The dataset was analysed to identify the most frequent aetiologies and their associations to outcome parameters.

RESULTS

We included 236 patients with a median age of 75 years and a median NIHSS score of 11. In-hospital mortality accounted for 30.5%. The most frequent pulmonary conditions on CT, in order of prevalence, included bronchitis/bronchiolitis (66.1%), atelectasis (66.1%), pleural effusion (60.6%), pneumonia (53%), pulmonary oedema (37.3%), and pulmonary artery embolism (27.5%). Bronchitis/bronchiolitis was an independent risk factor for mortality (OR = 3.17, 95% CI: 1.11-8.79, p = 0.03). A higher number of pulmonary conditions decreased the likelihood of discharge to home, and non-survivors had worse vital/laboratory parameters.

CONCLUSIONS

We identified six key pulmonary aetiologies of ARI after ischaemic stroke, with bronchitis/bronchiolitis notably linked to in-hospital mortality in our study cohort. An increased number of these acute pulmonary conditions decreased the likelihood of discharge to home. Early chest CT/CT-angiography may help to identify patients at high risk for in-hospital mortality and to initiate appropriate treatment early.

Influenza vaccine effect on risk of stroke occurrence: a systematic review and meta-analysis

Background

Stroke is a significant global cause of mortality and long-term disability, potentially influenced by infections that heighten systemic inflammation and thrombotic events. The full impact of influenza vaccination on stroke remains uncertain. This systematic review and meta-analysis aimed to investigate the association between influenza immunization and stroke incidence.

Methods

We searched for randomized controlled trials (RCTs), case-control, and cohort studies published in PubMed/Medline, Cochrane-Central-Register-of-Controlled-Trials (CENTRAL), and Embase until 5 December 2022, and identified articles investigating the effect of influenza vaccine on stroke occurrence. All articles were screened by two independent reviewers. We performed a meta-analysis to investigate the risk of stroke occurrence in vaccinated vs. unvaccinated individuals. The random-effects model was used in all statistical analyses.

Results

Among the 26 articles meeting our criteria, 10 were retrospective cohort studies, 9 were case-control studies, 3 were prospective cohort studies, 3 were RCTs and 1 case-series. Overall, the studies showed a significant decrease in the risk of stroke incidence/hospitalization among vaccinated patients (OR = 0.81, 95% CI [0.77-0.86], p = 0.00001). Furthermore, studies showed flu vaccine decreases the occurrence of mortality among stroke patients (OR = 0.50, 95% CI [0.37-0.68], p = 0.00001). Sub-group analysis revealed significant protective effect for patients with specific comorbidities including atrial fibrillation (OR = 0.68, 95% CI [0.57-0.81], p = 0.0001), diabetes (OR = 0.76, 95% CI [0.66-0.87], p = 0.0001), Chronic obstructive pulmonary disease (OR = 0.70, 95% CI [0.61-0.81], p = 0.00001), and hypertension (OR = 0.76, 95% CI [0.70-83], p = 0.00001).

Conclusion

The current meta-analysis further supports prior findings that influenza vaccination reduces stroke risk, particularly in patients with comorbidities. Guidelines should promote vaccination for at-risk individuals.

Impact of influenza, herpes zoster, and pneumococcal vaccinations on the incidence of cardiovascular events in subjects aged over 65 years: a systematic review

This systematic review aims to summarize the impact of vaccination against influenza, shingles, and pneumococcus on the incidence on the risk of cardiovascular events in the elderly. This protocol was developed in accordance with PRISMA guidelines. We conducted a literature search and identified all relevant articles published regarding the matter up to September 2022. We retrieved 38 studies (influenza vaccine = 33, pneumococcal vaccine = 5, and zoster vaccine = 2). A total of 28 and 2 studies have shown that influenza and pneumococcal vaccines significantly lower the risk of cardiovascular disease in the elderly. Also, repeated influenza vaccination shows a consistent and dose-dependent protective effect against acute coronary syndromes and stroke. Moreover, dual influenza and pneumococcal vaccination was associated with lower risks of some cardiovascular events (stroke, congestive heart failure, ischemic heart disease, and myocardial infarction). However, the impact of PCV13 on cardiovascular events has not been studied, nor has the currently recommended vaccination schedule (PCV13 + PPV23). As for herpes zoster vaccination, only the protective effect against stroke has been studied with the live attenuated herpes zoster vaccine, but no studies have been conducted with the recombinant subunit herpes zoster vaccine. This review outlines the benefits of the vaccines mentioned above beyond their preventive action on infectious diseases. It is intended for health professionals who wish to inform and advise their elderly patients.

A Systematic Review and Meta-Analysis of the Relationship between Receiving the Flu Vaccine with Acute Cerebrovascular Accident and Its Hospitalization in the Elderly

Background and Aims

In recent years, various studies have been conducted worldwide to investigate the relationship between receiving the flu vaccine with acute cerebrovascular accident or stroke and its hospitalization in the elderly; however, the results of these studies are contradictory. Therefore, this study was aimed at investigating the relationship between receiving the flu vaccine with stroke and its hospitalization in the elderly.

Methods

This study is a systematic review and meta-analysis of studies examining the relationship between receiving the flu vaccine with stroke and its hospitalization in the elderly during the years 1980 to 2021 which have been published in ISI Web of Science, Scopus PubMed, Cochrane, Science Direct, Google Scholar, and Embase. All analyses were performed by Stata 15, and the significance level in this study was considered <0.05.

Results

In the systematic search, 3088 articles were retrieved, considering the study criteria; finally, 14 studies were included in the meta-analysis. Based on the results of the meta-analysis, the odds ratio (OR) of occurrence and hospitalization of stroke compared to the nonvaccinated group in vaccine recipients is equal to 0.84 (95% confidence interval (CI): 0.78-0.90, P value ≤ 0.001). Publication bias was not observed in this study (P value = 0.101).

Conclusion

Getting the flu vaccine can reduce the risk of occurrence and hospitalization of stroke in the elderly by 16% (10%-22%). Therefore, receiving this vaccine as a preventive intervention for stroke in the elderly may be promising.

Influenza Vaccination and Risk of Ischemic Stroke: A Population-Based Case-Control Study

BACKGROUND AND OBJECTIVES

To assess the relationship between influenza vaccination in the general population and risk of a first ischemic stroke (IS) during pre-epidemic, epidemic, and postepidemic periods.

METHODS

A nested case-control study was conducted in a Spanish primary care database over 2001-2015. Individuals aged 40-99 years with at least 1 year registry and no history of stroke or cancer were selected to conform the source cohort, from which incident IS cases were identified and classified as cardioembolic or noncardioembolic. Five controls per case were randomly selected, individually matched with cases for exact age, sex, and date of stroke diagnosis (index date). A patient was considered vaccinated when he/she had a recorded influenza vaccination at least 14 days before the index date within the same season. Adjusted odds ratios (aORs) and their respective 95% CIs were computed through a conditional logistic regression. Pneumococcal vaccination was used as a negative control.

RESULTS

From a cohort of 3,757,621 patients, we selected 14,322 incident IS cases (9,542 noncardioembolic and 4,780 cardioembolic) and 71,610 matched controls. Of them, 41.4% and 40.5%, respectively, were vaccinated yielding a crude OR of 1.05 (95% CI 1.01-1.10). Vaccinated patients presented a higher prevalence of vascular risk factors, diseases, and comedication than those nonvaccinated, and after full adjustment, the association of influenza vaccination with IS yielded an aOR of 0.88 (95% CI 0.84-0.92), appearing early (aOR15-30 days 0.79; 95% CI 0.69-0.92) and slightly declining over time (aOR>150 days 0.92; 95% CI 0.87-0.98). A reduced risk of similar magnitude was observed with both types of IS, in the 3 epidemic periods, and in all subgroups analyzed (men, women, individuals younger and older than 65 years of age, and those with intermediate and high vascular risk). By contrast, pneumococcal vaccination was not associated with a reduced risk of IS (aOR 1.08; 95% CI 1.04-1.13).

DISCUSSION

Results are compatible with a moderate protective effect of influenza vaccine on IS appearing early after vaccination. The finding that a reduced risk was also observed in pre-epidemic periods suggests that either the "protection" is not totally linked to prevention of influenza infection or it may be partly explained by unmeasured confounding factors.

Changes in the Blood Viscosity in Patients With SARS-CoV-2 Infection

Coronavirus disease 2019 (COVID-19) is caused by a novel virus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2-induced hyperinflammation together with alteration of plasma proteins, erythrocyte deformability, and platelet activation, may affect blood viscosity. Thus, this review aimed to study the link between SARS-CoV-2 infection and alteration of blood viscosity in COVID-19 patients. In order to review findings related to hyperviscosity in COVID-19, we suggested a protocol for narrative review of related published COVID-19 articles. Hyperviscosity syndrome is developed in different hematological disorders including multiple myeloma, sickle cell anemia, Waldenstorm macroglobulinemia, polycythemia, and leukemia. In COVID-19, SARS-CoV-2 may affect erythrocyte morphology via binding of membrane cluster of differentiation 147 (CD147) receptors, and B and 3 proteins on the erythrocyte membrane. Variations in erythrocyte fragility and deformability with endothelial dysfunction and oxidative stress in SARS-CoV-2 infection may cause hyperviscosity syndrome in COVID-19. Of interest, hyperviscosity syndrome in COVID-19 may cause poor tissue perfusion, peripheral vascular resistance, and thrombosis. Most of the COVID-19 patients with a blood viscosity more than 3.5 cp may develop coagulation disorders. Of interest, hyperviscosity syndrome is more commonly developed in vaccine recipients who had formerly received the COVID-19 vaccine due to higher underlying immunoglobulin concentrations, and only infrequently in those who have not received the COVID-19 vaccine. Taken together, these observations are untimely too early to give a final connotation between COVID-19 vaccination and the risk for development of hyperviscosity syndrome, consequently prospective and retrospective studies are necessary in this regard.

Hyperviscosity syndrome in COVID-19 and related vaccines: exploring of uncertainties

Hyperviscosity syndrome (HVS) recently emerged as a complication of coronavirus disease 2019 (COVID-19) and COVID-19 vaccines. Therefore, the objectives of this critical review are to establish the association between COVID-19 and COVID-19 vaccines with the development of HVS. HVS may develop in various viral infections due to impairment of humoral and cellular immunity with elevation of immunoglobulins. COVID-19 can increase blood viscosity (BV) through modulation of fibrinogen, albumin, lipoproteins, and red blood cell (RBC) indices. HVS can cause cardiovascular and neurological complications in COVID-19 like myocardial infarction (MI) and stroke. HVS with or without abnormal RBCs function in COVID-19 participates in the reduction of tissue oxygenation with the development of cardio-metabolic complications and long COVID-19. Besides, HVS may develop in vaccine recipients with previous COVID-19 due to higher underlying Ig concentrations and rarely without previous COVID-19. Similarly, patients with metabolic syndrome are at the highest risk for propagation of HVS after COVID-19 vaccination. In conclusion, COVID-19 and related vaccines are linked with the development of HVS, mainly in patients with previous COVID-19 and underlying metabolic derangements. The possible mechanism of HVS in COVID-19 and related vaccines is increasing levels of fibrinogen and immunoglobulins. However, dehydration, oxidative stress, and inflammatory reactions are regarded as additional contributing factors in the pathogenesis of HVS in COVID-19. However, this critical review cannot determine the final causal relationship between COVID-19 and related vaccines and the development of HVS. Prospective and retrospective studies are warranted in this field.

Effects of influenza vaccination on the risk of cardiovascular and respiratory diseases and all-cause mortality

BACKGROUND

Influenza vaccination is a simple strategy recommended for the prevention of influenza infection and its complications. This meta-analysis aimed to provide current supportive evidence for the breadth and validity of the observed protective effects of influenza vaccination on cardiovascular and respiratory adverse outcomes and all-cause mortality in older adults and in general adult population.

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library to identify all published studies comparing influenza vaccination with placebo from the database inception to November 11, 2018. These included studies reporting the associations of influenza vaccination with the risk of aforementioned adverse outcomes.

RESULTS

The pooled adjusted relative risks among influenza-vaccinated people relative to unvaccinated people for the outcomes of interest were 0.74 (95 % confidence interval [CI] = 0.70-0.78) for cardiovascular diseases (63 studies), 0.82 (95 % CI = 0.75-0.91) for respiratory diseases (29 studies), and 0.57 (95 % CI = 0.51-0.63) for all-cause mortality (43 studies). We performed subgroup analysis of age, sex, and region/country and found that these protective effects were evident in the general adult population and particularly robust in older adults and in those with pre-existing specific diseases.

CONCLUSION

Influenza vaccine is associated with a significant risk reduction of cardiovascular and respiratory adverse outcomes as well as all-cause mortality. Such a preventative measure can benefit the general population as well as those in old age and with pre-existing specific diseases.

The outcome and the influencing factors of the age of onset in post-mortem of chronic bronchitis patients: a retrospective study

Purpose

Chronic bronchitis is thought to occur in elderly patients, and smoking seems to be an important risk factor. The outcomes related to the age of onset in patients with chronic bronchitis are still unclear.

Patients and methods

A retrospective study was conducted on deceased patients whose diagnosis included bronchitis from 2010 to 2016. Patients were separated into two groups according to the age of onset (Group I, age ≤50 years old; Group II, age >50 years old). Information regarding disease course, smoking history, death age, number of admissions per year, Hugh Jones Index, and self-reported comorbidities of the patients was recorded.

Results

The courses of chronic cough and sputum were 33.38±7.73 years and 14.44±8.60 years in Group I and Group II, respectively (p<0.05). The death ages of Group I and Group II were 77.65±7.87 years and 84.69±6.67 years, respectively (p<0.05). There was a significant negative correlation between the number of hospital admissions per year and the age of onset. The age of onset was negatively associated with daily smoking count (r=−0.210) and total smoking count (r=−0.146). In Group I, there were fewer cases of coronary heart disease (OR =0.41 [0.24–0.71]), neurological diseases (OR =0.48 [0.24–0.97]), and total comorbidities (OR =0.67 [0.54–0.85]) than in Group II.

Conclusion

Patients with early onset chronic bronchitis had a longer history, younger death age, poorer health status, and lower incidence of comorbidities.

Association between influenza vaccination and reduced risks of major adverse cardiovascular events in elderly patients

BACKGROUND

This study was conducted to determine the protective effect of influenza vaccine against primary major adverse cardiovascular events (MACEs) in elderly patients, especially those with influenza-like illness (ILI).

METHODS

This retrospective, population-based case-control study of an elderly population (age≥65 years) was conducted using Taiwan's National Health Insurance Research Database (2000-2013). One control was selected for each MACE case (n=80,363 each), matched according to age, year of study entry, and predisposing factors for MACEs. ILI and MACEs (myocardial infarction [MI] and ischemic stroke) were defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification. Odds ratios (ORs) were calculated for the association between MACEs and vaccination.

RESULTS

Influenza vaccination received in the previous year was associated with reduced risks of primary MACEs overall (adjusted OR [aOR] 0.80, 95% CI 0.78-0.82, P<.001), MI (aOR 0.80, 95% CI 0.76-0.84, P<.001), and ischemic stroke (aOR 0.80, 95% CI 0.77-0.82, P<.001). ILI diagnosed in the previous year was associated with increased risks of MACEs (aOR 1.24, 95% CI 1.18-1.29, P<.001), MI (aOR 1.46, 95% CI 1.34-1.59, P<.001), and ischemic stroke (aOR 1.16, 95% CI 1.10-1.22, P<.001). Vaccination attenuated the heightened risks associated with ILI (MACEs: aOR 0.99, 95% CI 0.92-1.07, P=.834; MI: aOR 1.05, 95% CI 0.92-1.21, P=.440; ischemic stroke: aOR 0.96, 95% CI 0.89-1.05, P=.398).

CONCLUSIONS

Results of this study suggest that influenza vaccination is associated with reduced primary MACE risks in the elderly population, including those with ILI.

Effect of Influenza Vaccination on Risk of Stroke: A Systematic Review and Meta-Analysis

Background: Despite the presence of a strong association between influenza infection and stroke, whether influenza vaccination reduces the risk of stroke is yet a matter of controversy. We conducted a meta-analysis to determine whether influenza vaccination protects against stroke. Methods: We searched PubMed, EMBASE, and the Cochrane Library from database inception date to November 18, 2016, without language restrictions, to identify studies investigating the effect of influenza vaccination on subsequent risk of stroke. We conducted a meta-analysis to quantify the risk of stroke in overall and subgroup analyses and calculated a pooled OR for developing stroke with a 95% CI. Publication bias was assessed by Begg's rank correlation test. Results: Eleven studies fulfilled our inclusion criteria. In a random-effects model, vaccinated individuals had a decreased risk of stroke compared with unvaccinated individuals (OR 0.82; 95% CI 0.75-0.91; p < 0.001). The relationship between influenza vaccination and stroke risk remained robust in subgroup analyses. The significant effect of influenza vaccination was associated with ascertainment of vaccination status and stage of prevention. Conclusion: Vaccination against influenza is associated with a lower risk of stroke. Well-designed prospective studies are needed to provide stronger evidence of the protective effect of influenza vaccination against stroke.

Chronic Obstructive Pulmonary Disease and the Risk of Stroke

RATIONALE

Chronic obstructive pulmonary disease (COPD) has been identified as a risk factor for cardiovascular diseases such as myocardial infarction. The role of COPD in cerebrovascular disease is, however, less certain. Although earlier studies have suggested that the risk for stroke is also increased in COPD, more recent investigations have generated mixed results.

OBJECTIVES

The primary objective of our review was to quantify the magnitude of the association between COPD and stroke. We also sought to clarify the nature of the relationship between COPD and stroke by investigating whether the risk of stroke in COPD varies with age, sex, smoking history, and/or type of stroke and whether stroke risk is modified in particular COPD phenotypes.

RESULTS

The MEDLINE and EMBASE databases were searched in May 2016 to identify articles that compared stroke outcomes in people with and without COPD. Studies were grouped by study design to distinguish those that reported prevalence of stroke (cross-sectional studies) from those that estimated incidence (cohort or case-control studies). In addition, studies were stratified according to study population characteristics, the nature of COPD case definitions, and adjustment for confounding (smoking). Heterogeneity was assessed using the I2 statistic. We identified 5,493 studies, of which 30 met our predefined inclusion criteria. Of the 25 studies that reported prevalence ratios, 11 also estimated prevalence odds ratios. The level of heterogeneity among the included cross-sectional studies did not permit the calculation of pooled ratios, save for a group of four studies that estimated prevalence odds ratios adjusted for smoking (prevalence odds ratio, 1.51; 95% confidence interval, 1.09-2.09; I2 = 45%). All 11 studies that estimated relative risk for nonfatal incident stroke reported increased risk in COPD. Adjustment for smoking invariably reduced the magnitude of the associations.

CONCLUSIONS

Although both prevalence and incidence of stroke are increased in people with COPD, the weight of evidence does not support the hypothesis that COPD is an independent risk factor for stroke. The possibility remains that COPD is causal in certain subsets of patients with COPD and for certain stroke subtypes.

Infection, vaccination, and childhood arterial ischemic stroke: Results of the VIPS study

OBJECTIVES

Minor infection can trigger adult arterial ischemic stroke (AIS) and is common in childhood. We tested the hypotheses that infection transiently increases risk of AIS in children, regardless of stroke subtype, while vaccination against infection is protective.

METHODS

The Vascular Effects of Infection in Pediatric Stroke study is an international case-control study that prospectively enrolled 355 centrally confirmed cases of AIS (29 days-18 years old) and 354 stroke-free controls. To determine prior exposure to infections and vaccines, we conducted parental interviews and chart review.

RESULTS

Median (interquartile range) age was 7.6 years for cases and 9.3 for controls (p = 0.44). Infection in the week prior to stroke, or interview date for controls, was reported in 18% of cases, vs 3% of controls, conferring a 6.3-fold increased risk of AIS (p < 0.0001); upper respiratory infections were most common. Prevalence of preceding infection was similar across stroke subtypes: arteriopathic, cardioembolic, and idiopathic. Use of vasoactive cold medications was similarly low in both groups. Children with some/few/no routine vaccinations were at higher stroke risk than those receiving all or most (odds ratio [OR] 7.3, p = 0.0002). In an age-adjusted multivariate logistic regression model, independent risk factors for AIS included infection in the prior week (OR 6.3, p < 0.0001), undervaccination (OR 8.2, p = 0.0004), black race (compared to white; OR 1.9, p = 0.009), and rural residence (compared to urban; OR 3.0, p = 0.0003).

CONCLUSIONS

Infection may act as a trigger for childhood AIS, while routine vaccinations appear protective. Hence, efforts to reduce the spread of common infections might help prevent stroke in children.

Impact of chronic inflammatory airway disease on stroke severity and long-term survival after ischemic stroke--a retrospective analysis

Background

Chronic inflammatory airway disease (CIAD) has emerged as independent risk factor for cardiovascular mortality and ischemic stroke but the impact of co-existing CIAD in patients with ischemic stroke is less clear.

Methods

We retrospectively analyzed 1013 patients with acute ischemic stroke who were consecutively admitted to the Department of Neurology, Charité - Universitätsmedizin Berlin, Germany within one year. Mean follow-up was 80 months (IQR 32–85 months). Using multivariable regression models we analyzed the impact of CIAD (defined as chronic obstructive pulmonary disease or asthma bronchiale) on stroke severity and outcome.

Results

Co-existing CIAD was evident in 7.1 % (n = 72) of all patients with acute ischemic stroke. Baseline characteristics of stroke patients with CIAD did not differ significantly from ischemic stroke patients without CIAD. Age (OR 1.17 [95 % CI 1.03-1.37] per decade), atrial fibrillation (OR 3.43 [95 % CI 2.47-4.78]) and coronary artery disease (OR 1.51 [95 % CI 1.07–2.14]) but not a history of CIAD (p = 0.30) were associated with severe stroke (NIHSS≥11) on hospital admission. Age (HR 1.70 [95 % CI 1.53-1.87] per decade), peripheral artery disease (HR 1.91 [95 % CI 1.35-2.7]), stroke severity at hospital admission (NIHSS per point HR 1.08 [95 % CI 1.06-1.10]), and history of CIAD (HR 1.43 [95 % CI 1.02-2.00]) were independently associated with mortality during long-term follow-up. However, CIAD was not significantly associated with short-term mortality after stroke.

Conclusion

Co-existing CIAD showed no significant association with stroke severity at hospital admission and early mortality after ischemic stroke. CIAD was negatively associated with long-term survival after ischemic stroke.

Influenza, influenza-like symptoms and their association with cardiovascular risks: a systematic review and meta-analysis of observational studies

AIMS

To synthesise the evidence relating influenza and influenza-like symptoms to the risks of myocardial infarction (MI), heart failure (HF) and stroke.

METHODS

We conducted a systematic review and meta-analysis of the evidence relating influenza and influenza-like symptoms to the risks of MI, HF and stroke. We systematically searched all MEDLINE and EMBASE entries up to August 2014 for studies of influenza vs. the cardiovascular outcomes above. We conducted random effects meta-analysis using inverse variance method for pooled odds ratios (OR) and evaluated statistical heterogeneity using the I(2) statistic.

RESULTS

We identified 12 studies with a total of 84,003 participants. The pooled OR for risk of MI vs. influenza (serologically confirmed) was 1.27 (95% CI, confidence interval 0.54-2.95), I(2)  = 47%, which was significant for the only study that adjusted for confounders (OR 5.50, 95% CI 1.31-23.13). The pooled OR for risk of MI vs. influenza-like symptoms was 2.17 (95% CI 1.68-2.80), I(2)  = 0%, which was significant for both unadjusted (OR 2.23, 95% CI 1.65-3.01, five studies) and adjusted studies (OR 2.01, 95% CI 1.24-3.27, two studies). We found one study that evaluated stroke risk, one study in patients with HF, and one that evaluated mortality from MI - all of these studies suggested increased risks of events with influenza-like symptoms.

CONCLUSIONS

There is an association between influenza-like illness and cardiovascular events, but the relationship is less clear with serologically diagnosed influenza. We recommend renewed efforts to apply current clinical guidelines and maximise the uptake of annual influenza immunisation among patients with cardiovascular diseases, to decrease their risks of MI and stroke.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Influenza and pneumococcal vaccination and risk of stroke or transient ischaemic attack-matched case control study

BACKGROUND

Evidence that respiratory infections trigger stroke suggests that influenza or pneumococcal vaccination might prevent stroke. We aimed to investigate whether influenza or pneumococcal vaccination or both together were associated with reduced risk of stroke or transient ischaemic attack (TIA).

METHODS

We used a matched 1:1 case-control design with data from the United Kingdom General Practice Research Database. Cases, aged 18 years or above with stroke (fatal or non-fatal) and TIA during September 2001 to August 2009, were compared with controls matched for age, sex, calendar time and practice, adjusting for cardiovascular risk factors, vaccine risk groups, comorbidity and indicators of functional ability.

RESULTS

We included 26,784 cases of stroke and 20,227 cases of TIA with equal numbers of matched controls. Influenza vaccination within-season was associated with 24% reduction in stroke risk (adjusted OR 0.76, 95% CI 0.72 to 0.80) but no reduction in TIA (1.03, 0.98 to 1.09). Stroke risk was significantly lower with early (September to mid-November: 0.74, 0.70 to 0.78) but not later influenza vaccination (mid-November onwards: 0.92, 0.83 to 1.01). Associations persisted after multiple imputation of missing data and sensitivity analysis for unmeasured confounders. Pneumococcal vaccination was not associated with a reduction in risk of stroke (0.98, 0.94 to 1.00) or TIA (1.15, 1.08 to 1.23).

CONCLUSIONS

Influenza vaccination was associated with a 24% reduction in risk of stroke but not TIA. Pneumococcal vaccination was not associated with reduced risk of stroke or TIA. This has important implications for potential benefits of influenza vaccine.

Subarachnoid hemorrhage incidence in the United States does not vary with season or temperature

BACKGROUND AND PURPOSE

Previous studies have suggested seasonal variations in rates of spontaneous rupture of intracranial aneurysms, leading to potentially devastating SAH. In an effort to identify a seasonal effect, variation in SAH incidence and in-hospital mortality rates were examined as they relate to admission month, temperature, and climate using HCUP's Nationwide Inpatient Sample.

MATERIALS AND METHODS

Cases of nontraumatic SAH and subsequent in-hospital mortality were extracted from the 2001-2008 NIS and associated with month of occurrence, local average monthly temperatures, and USDA climate zone. Multivariate regression analysis was used to study how admission month, temperature, and climate affected SAH admission and mortality rates.

RESULTS

Among 57,663,486 hospital admissions from the 2001-2008 NIS, 52,379 cases of spontaneous SAH (ICD-9-CM 430) and 13,272 cases of subsequent in-hospital mortality were identified. SAH incidence and in-hospital mortality rates were not significantly correlated with a monthly/seasonal effect (incidence, χ(2) = 2.94, P = .99; mortality, χ(2) = 6.91, P = .81). However, SAH incidence significantly varied with climate (P < .0001, zones 11 and 7) but not with temperature (P = .1453), whereas average monthly temperature and climate had no significant correlation with in-hospital mortality (temperature, P = .3005; climate, P = .0863).

CONCLUSIONS

We identified no significant monthly or temperature-related effect in the incidence of SAH. Our data suggest that certain climate zones within the United States may be associated with significantly different SAH incidence, but the origins of these differences remain unclear and are probably unrelated to meteorologic variables.

Neurological and endocrinological disorders: orphans in chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) are often characterised by a range of characteristic co-morbidities that interfere with their pulmonary disease. In addition to a mere association with co-morbidities, a complex pathophysiological interaction and mutual augmentation occurs between COPD and its co-morbidities that may result in disease progression and increased morbidity and mortality. An interdisciplinary approach is required both for diagnosis and treatment to target co-morbidities early in the course of the disease. This review summarizes the current knowledge of the interaction with cerebrovascular disease and endocrinological co-morbidities in COPD patients. There is growing evidence that COPD is an independent risk factor for ischemic stroke, increasing the risk about twofold. Stroke risk in COPD patients increases with the severity of the disease as measured by the degree of airflow limitation. The presence of cardiovascular risk factors is of particular importance for stroke prevention in COPD patients. Endocrinological co-morbidities are also important and many are associated with increased cardiovascular risk. Impaired glucose metabolism ranges from insulin resistance to overt diabetes mellitus, which is a frequent finding and is associated with worse outcome.

Stroke and the immune system: from pathophysiology to new therapeutic strategies

Stroke is the second most common cause of death worldwide and a major cause of acquired disability in adults. Despite tremendous progress in understanding the pathophysiology of stroke, translation of this knowledge into effective therapies has largely failed, with the exception of thrombolysis, which only benefits a small proportion of patients. Systemic and local immune responses have important roles in causing stroke and are implicated in the primary and secondary progression of ischaemic lesions, as well as in repair, recovery, and overall outcome after a stroke. However, potential therapeutic targets in the immune system and inflammatory responses have not been well characterised. Development of novel and effective therapeutic strategies for stroke will require further investigation of these pathways in terms of their temporal profile (before, during, and after stroke) and risk-to-benefit therapeutic ratio of modulating them.

The Association Between Weather and Spontaneous Subarachnoid Hemorrhage: An Analysis of 155 US Hospitals

BACKGROUND:

A seasonal and meteorological influence on the incidence of spontaneous subarachnoid hemorrhage (SAH) has been suggested, but a consensus in the literature has yet to emerge.

OBJECTIVE:

This study examines the impact of weather patterns on the incidence of SAH using a geographically broad analysis of hospital admissions and represents the largest study of the topic to date.

METHODS:

We retrospectively analyzed SAH admissions to 155 US hospitals during the calendar years 2004 to 2008 (N = 7758). Daily weather readings for temperature, pressure, and humidity were obtained for the same period from National Oceanic and Atmospheric Administration weather stations located near each hospital. The daily values of each weather variable were associated with the daily volume of SAH admissions using a combination of correlation and time-series analyses.

RESULTS:

No seasonal trends were observed in the monthly volume of SAH admissions during the study period. No significant correlation was detected between the daily SAH admission volume and the day's weather, the previous day's weather, or the 24-hour weather change.

CONCLUSION:

This study represents the most comprehensive investigation of the association between weather and spontaneous SAH to date. The results suggest that neither season nor weather significantly influences the incidence of SAH.

Which dietary and lifestyle behaviours may be important in the aetiology (and prevention) of stroke?

Prevention of stroke requires optimal control of causal risk factors. However, only three-quarters of all strokes can be attributable to known causal risk factors. We aimed to identify novel risk factors for acute stroke in 48 patients with acute (<1 week) stroke admitted to Royal Perth Hospital Stroke Unit and 47 controls matched for age and sex from the northeast Perth metropolitan area. Patients and controls were interviewed, and had physical measurements and blood taken. Multiple odds ratios (OR) for risk factors, with 95% confidence intervals (CI), were calculated by unconditional multiple logistic regression. Mediterranean diet (OR: 0.1; 95% CI, 0.02-0.4), increased waist-to-hip ratio (OR 4.0, 95% CI, 1.5-11), physical activity during leisure time (OR 0.2; 95% CI, 0.1-0.9), periodontal disease (OR 6.4; 95% CI, 1.5-27), and acute febrile illness (OR 14; 95% CI, 1.5-127) were associated significantly and independently with ischaemic stroke. These preliminary data suggest that certain dietary and lifestyle behaviours may play as important a role in the aetiology (and prevention) of stroke as other conventional causal risk factors for stroke. However, these associations need confirmation from larger randomised trials given the small sample size of the current study.

Acute ischemic stroke and infections

We present an overview of multiple infections in relation to acute ischemic stroke and the therapeutic options available. Conditions that are a direct cause of stroke (infectious endocarditis, meningoencephalitides, and human immunodeficiency virus infection), the pathophysiologic mechanism responsible for stroke, and treatment dilemmas are presented. Independently or in conjunction with conventional risk factors, chronic and acute infections can trigger an acute ischemic stroke through an accelerated process of atherosclerosis and immunohematologic alterations. Acute ischemic stroke has a negative impact on the antibacterial immune response, leading to stroke-induced immunodepression and infections, the most common poststroke medical complications. Poststroke infections are independent predictors of poor outcome. Antibiotic trials for poststroke infection prevention are reviewed. Although antibiotic prophylaxis is not the standard of care in acute stroke, current guidelines support prompt treatment of stroke-related infections.

Association of Symptoms of Chronic Bronchitis and Frequent Flu-Like Illnesses With Stroke

Background and Purpose— Acute and several chronic infectious diseases increase the risk of stroke. We tested the hypothesis that chronic bronchitis and frequent flu-like illnesses are independently associated with the risk of stroke or transient ischemic attack (TIA).

Methods— We assessed symptoms of chronic bronchitis, frequency of flu-like illnesses, and behavior during acute febrile infection in 370 consecutive patients with ischemic or hemorrhagic stroke or TIA and 370 age- and sex-matched control subjects randomly selected from the population.

Results— Cough with phlegm during ≥3 months per year (grade 2 symptoms of chronic bronchitis) was associated with stroke or TIA independent from smoking history, other risk factors, and school education (odds ratio [OR] 2.63, 95% confidence interval [CI] 1.17 to 5.94; P =0.021). There was also an independent association between frequent flu-like infections (>2 per yr) and stroke/TIA (OR 3.54; 95% CI 1.52 to 8.27; P =0.003). Simultaneous assessment of chronic bronchitis and frequent flu-like infections did not attenuate the effect of either factor. Patients reported more often than control subjects to continue to work despite febrile infection (OR 3.68, 95% CI 1.80 to 7.52, multivariate analysis).

Conclusions— Our results suggest that chronic bronchitis is among those chronic infections that increase the risk of stroke. Independent from chronic bronchitis, a high frequency of flu-like illnesses may also be a stroke risk factor. Infection-related behavior may differ between stroke patients and control subjects.