Acute infection contributes to racial disparities in stroke mortality

Stroke risk after varicella-zoster virus infection: a systematic review and meta-analysis

Varicella-zoster virus (VZV) infection may cause vascular inflammatory changes leading to an increased risk of stroke. Previous studies have focused on the risk of stroke and less on changes in stroke risk and prognosis. We aimed to explore the changing patterns of stroke risk and stroke prognosis after VZV infection. This study is a systematic review and meta-analysis. We searched PubMed, Embase, and the Cochrane Library for studies on stroke after VZV infection between January 1, 2000, and October 5, 2022. Relative risks were combined for the same study subgroups using a fixed-effects model and pooled across studies using a random-effects model. 27 studies met the requirements, including 17 herpes zoster (HZ) studies and ten chickenpox studies. There was an increased risk of stroke after HZ, and this risk decreased over time: relative risk 1.80 (95% CI 1.42-2.29) within 14 days, 1.61 (95% CI 1.43-1.81) within 30 days, 1.45 (95% CI 1.33-1.58) within 90 days, 1.32 (95% CI 1.25-1.39) within 180 days, 1.27 (95% CI 1.15-1.40) at one year and 1.19 (95% CI 0.90-1.59) after one year, with the same trend in the stroke subtype. The risk of stroke after herpes zoster ophthalmicus was higher, with a maximum relative risk of 2.26 (95% CI 1.35-3.78). The risk of stroke after HZ was higher in patients aged around 40 years: relative risk 2.53 (95% CI 1.59-4.02), and similar in men and women. Also, after pooling studies of post-chickenpox stroke, we found that the middle cerebral artery and its branches were most frequently involved (78.2%), with a better prognosis in most patients (83.1%) and less frequent vascular persistence progression (8.9%). In conclusion, the risk of stroke increases after VZV infection, decreasing over time. Post-infection vascular inflammatory changes often occur in the middle cerebral artery and its branches, with a better prognosis in most patients and less frequent persistent progression.

[Infections and inflammation in the development of stroke]

The review systematizes data on the role of infectious diseases and systemic inflammation in the pathogenesis of stroke. Various risk factors for stroke associated with pro-inflammatory reactions and their contribution to the pathogenesis of cerebrovascular pathology are analyzed. The interaction of systemic inflammation with hemostasis disturbances and clots formation, activation of autoreactive clones of cytotoxic lymphocytes, the progression of endothelial damage, and other processes is shown. Along with infection, these factors increase the risk of stroke. The key mechanisms of the pathogenesis from the development of acute or chronic inflammation to the preconditions of stroke are presented. The mechanisms of the acting of the infectious process as a trigger factor and/or medium-term or long-term risk factors of stroke are described. A separate section is devoted to the mechanisms of developing cerebrovascular diseases after COVID-19. Identifying an increased risk of stroke due to infection can be of great preventive value. Understanding of this risk by specialists followed by correction of drug therapy and rehabilitation measures can reduce the incidence of cerebrovascular complications in infectious patients.

Racial and ethnic disparities in viral acute respiratory infections in the United States: protocol of a systematic review

BACKGROUND

The COVID-19 pandemic caused by SARS-CoV-2 has highlighted consistent inequities in incidence, disease severity, and mortality across racial and ethnic minority populations in the United States (US) and beyond. While similar patterns have been observed with previous viral respiratory pathogens, to date, no systematic review has comprehensively documented these disparities or potential contributing factors. In response, this review aims to synthesize data on racial and ethnic disparities in morbidity and mortality due to viral acute respiratory infections (ARI) other than SARS-CoV-2. This review will focus on understanding structural health and social factors to contextualize race and ethnicity driving these disparities in the US.

METHODS

We will conduct a systematic review of studies published from January 1, 2002, onward. Our search will include PubMed/MEDLINE, EBSCO Host-CINAHL Plus, PsycInfo, EMBASE, and Cochrane Library databases to identify relevant articles. We will include studies of any design that describe racial/ethnic disparities associated with viral ARI conducted in the US. Primary outcomes include incidence, disease severity or complication, hospitalization, or death attributed to ARI. Secondary outcomes include uptake of preventive interventions including vaccination, handwashing, social distancing, and wearing masks. Two reviewers will independently screen all citations, full-text articles, and abstract relevant data. Data characterizing individual-, community-, and structural-level factors associated with these disparities will be abstracted to better understand the underlying structural inequities contributing to racial disparities in ARI. We will assess the methodological quality of all studies and will conduct meta-analyses using random effects models if appropriate.

DISCUSSION

Findings from this systematic review will shed light on patterns of racial and ethnic disparities in viral ARI in the United States to support mathematical modeling of epidemic trajectories, intervention impact, and structural drivers of transmission, including structural racism. Moreover, data emerging from this review may reignite pandemic preparedness focused on communities with specific vulnerabilities related to living and working conditions given prevailing structural inequities, thus facilitating improved future pandemic responses to novel or endemic viral respiratory pathogens.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020219771.

Racial and Ethnic Disparities in Viral Acute Respiratory Infections in the United States: Protocol of a Systematic Review

Background:

The COVID-19 pandemic caused by SARS-CoV-2 has highlighted consistent inequities in the risk of infection, severity of disease, or mortality across racial and ethnic minority populations in the United States and beyond. Although novel, SARS-CoV-2 shares commonalities in transmission dynamics with other viral respiratory pathogens where similar disparities in morbidity and mortality have been documented. However, to date, there has not been a systematic review of disparities in viral respiratory pathogens. In response, this review aims to synthesize data on racial and ethnic disparities in morbidity and mortality due to viral acute respiratory infections (ARI) other than SARS-CoV-2. In particular, this review will focus on understanding structural health and social factors outside of race and ethnicity driving these disparities in the United States.

Methods:

We will conduct a systematic review of studies published between January 1, 2002 and September 30, 2020 that capture data on racial and ethnic disparities associated with increased incidence, disease severity, risk of hospitalization and/or death in viral ARI in the United States. Data characterizing individual-, community-, and structural-level factors associated with these disparities will be abstracted to better understand the underlying structural inequities contributing to racial disparities in ARI. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines will be used with reviewers employing COVIDENCE to conduct two independent rounds of title/abstract and full text reviews for all articles. A built-in tool in COVIDENCE will be used for data abstraction.

Discussion:

Findings from this systematic review will shed light on patterns of racial and ethnic disparities in viral ARI in the United States. Leveraging these data can support predictive studies of the differential impacts of COVID-19 across the United States as well as adaptive intervention strategies mitigating structural inequities, including structural racism, driving both incidence and disparities in marginalized communities. Moreover, data emerging from this review may reignite pandemic preparedness focused on vulnerable communities given structural inequities, facilitating improved future pandemic responses to novel or endemic viral respiratory pathogens in the United States.

Systematic review registration:

PROSPERO CRD42020219771

Hospitalized Infection as a Trigger for Acute Ischemic Stroke: The Atherosclerosis Risk in Communities Study

BACKGROUND AND PURPOSE

Acute triggers for ischemic stroke, which may include infection, are understudied, as is whether background cardiovascular disease (CVD) risk modifies such triggering. We hypothesized that infection increases acute stroke risk, especially among those with low CVD risk.

METHODS

Hospitalized strokes and infections were identified in the Atherosclerosis Risk in Communities (ARIC) cohort. A case-crossover design and conditional logistic regression were used to compare hospitalized infections among patients with stroke (14, 30, 42, and 90 days before stroke) with corresponding control periods 1 year and 2 years before stroke. Background CVD risk was assessed at both visit 1 and the visit most proximal to stroke, with risk dichotomized at the median.

RESULTS

A total of 1008 adjudicated incident ischemic strokes were included. Compared with control periods, hospitalized infection was more common within 2 weeks before stroke (14-day odds ratio [OR], 7.7; 95% CI, 2.1-27.3); the strength of association declined with increasing time in the exposure window before stroke (30-day OR, 5.7 [95% CI, 2.3-14.3]; 42-day OR, 4.5 [95% CI, 2.0-10.2]; and 90-day OR, 3.6 [95% CI, 2.1-6.5]). Stroke risk was higher among those with low compared with high CVD risk, with this interaction reaching statistical significance for some exposure periods.

CONCLUSIONS

These results support the hypothesis that hospitalized infection is a trigger of ischemic stroke and may explain some cryptogenic strokes. Infection control efforts may prevent strokes. CVD preventive therapies may prevent strokes if used in the peri-infection period, but clinical trials are needed.

From Data to Action: Neuroepidemiology Informs Implementation Research for Global Stroke Prevention and Treatment

As a scientific field of study, neuroepidemiology encompasses more than just the descriptive study of the frequency, distribution, determinants and outcomes of neurologic diseases in populations. It also includes experimental aspects that span the full spectrum of clinical and population science research. As such, neuroepidemiology has a strong potential to inform implementation research for global stroke prevention and treatment. This review begins with an overview of the progress that has been made in descriptive and experimental neuroepidemiology over the past quarter century with emphasis on standards for evidence generation, critical appraisal of that evidence and impact on clinical and public health practice at the national, regional and global levels. Specific advances made in high-income countries as well as in low- and middle-income countries are presented. Gaps in implementation as well as evidence gaps in stroke research, stroke burden, clinical outcomes and disparities between developed and developing countries are then described. The continuing need for high quality neuroepidemiologic data in low- and middle-income countries is highlighted. Additionally, persisting disparities in stroke burden and care by sex, race, ethnicity, income and socioeconomic status are discussed. The crucial role that national stroke registries have played in neuroepidemiologic research is also addressed. Opportunities presented by new directions in comparative effectiveness and implementation research are discussed as avenues for turning neuroepidemiological insights into action to maximize health impact and to guide further biomedical research on neurological diseases.

Outcomes after Stroke in Patients with Previous Pressure Ulcer: A Nationwide Matched Retrospective Cohort Study

BACKGROUND

Factors associated with poststroke adverse events were not completely understood. The purpose of this study was to investigate whether stroke patients with previous pressure ulcers had more adverse events after stroke.

METHODS

Using the claims data from Taiwan's National Health Insurance Research Database, we conducted a retrospective cohort study matched by propensity score. Three thousand two first-ever stroke patients with previous pressure ulcer and 3002 first-ever stroke patients without pressure ulcer were investigated between 2002 and 2009. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of complications and 30-day mortality after stroke associated with previous pressure ulcer were calculated in the multivariate logistic regressions.

RESULTS

Patients with pressure ulcer had significantly higher risk than control for poststroke urinary tract infection (OR: 1.56, 95% CI: 1.38-1.78), pneumonia (OR: 1.35, 95% CI: 1.16-1.58), gastrointestinal bleeding (OR: 1.31, 95% CI: 1.04-1.66), and epilepsy (OR: 1.84, 95% CI: 1.83-1.85). Stroke patients with pressure ulcer had increased 30-day poststroke mortality (OR: 2.01, 95% CI: 1.55-2.61), particularly in those treated with debridement (OR: 2.87, 95% CI: 1.85-4.44) or high quantity of antibiotics (OR: 4.01, 95% CI: 2.10-7.66). Pressure ulcer was associated with poststroke mortality in both genders and patients aged 60 years or older.

CONCLUSIONS

This study showed increased poststroke complications and mortality in patients with previous pressure ulcer, which suggests the urgent need for monitoring stroke patients for pressure ulcer history.

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.

The association of depression, cognitive impairment without dementia, and dementia with risk of ischemic stroke: a cohort study

OBJECTIVE

To determine if depression, cognitive impairment without dementia (CIND), and/or dementia are each independently associated with risk of ischemic stroke and to identify characteristics that could modify these associations.

METHODS

This retrospective-cohort study examined a population-based sample of 7031 Americans older than 50 years participating in the Health and Retirement Study (1998-2008) who consented to have their interviews linked to their Medicare claims. The eight-item Center for Epidemiologic Studies Depression Scale and/or International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) depression diagnoses were used to identify baseline depression. The Modified Telephone Interview for Cognitive Status and/or ICD-9-CM dementia diagnoses were used to identify baseline CIND or dementia. Hospitalizations for ischemic stroke were identified via ICD-9-CM diagnoses.

RESULTS

After adjusting for demographics, medical comorbidities, and health-risk behaviors, CIND alone (odds ratio [OR] = 1.37, 95% confidence interval [CI] = 1.11-1.69) and co-occurring depression and CIND (OR = 1.65, 95% CI = 1.24-2.18) were independently associated with increased odds of ischemic stroke. Depression alone was not associated with odds of ischemic stroke (OR = 1.11, 95% CI = 0.88-1.40) in unadjusted analyses. Neither dementia alone (OR = 1.09, 95% CI = 0.82-1.45) nor co-occurring depression and dementia (OR = 1.25, 95% CI = 0.89-1.76) were associated with odds of ischemic stroke after adjusting for demographics.

CONCLUSIONS

CIND and co-occurring depression and CIND are independently associated with increased risk of ischemic stroke. Individuals with co-occurring depression and CIND represent a high-risk group that may benefit from targeted interventions to prevent stroke.