Risk of stroke and myocardial infarction after influenza-like illness in New York State

Podcast: Need for Quality Evidence for Decision-Making on Seasonal Influenza Vaccines

Seasonal influenza is usually considered an acute respiratory infection with a full recovery within a week. In addition to the traditional outcomes, there is now evidence of indirect effects in terms of neurological and functional complications. Major organ systems can be affected, underlining the need for preventative measures against infection. The aim of this podcast, featuring Dr. Ann Falsey, Dr. Stefania Maggi, and Dr. Tor Biering-Sørensen, is to outline influenza complications beyond acute respiratory disease, as well as discussing the need for quality of evidence when evaluating influenza vaccines. Assessing the benefits of vaccination can be challenging. To ensure a high quality of evidence, the innovative randomization of patients within the study design to avoid bias and the assessment of additional outcomes beyond immunogenicity as well as the inclusion of a broad population-including frail or vulnerable individuals-are essential. Studies leveraging nationwide registries such as the DANFLU-2 trial in Denmark highlight the advantages of a digitalized healthcare system for conducting large-scale randomized trials. Furthermore, large-scale trials such as the Gravenstein study have supplied a sizable body of evidence supporting the use of high-dose influenza vaccine in older adults. In conclusion, achieving a high quality of evidence is key for decision-making on seasonal influenza vaccines.

Temporal Association Among Influenza-Like Illness, Cardiovascular Events, and Vaccine Dose in Patients With High-Risk Cardiovascular Disease: Secondary Analysis of a Randomized Clinical Trial

Importance

Influenza-like illness (ILI) activity has been associated with increased risk of cardiopulmonary (CP) events during the influenza season. High-dose trivalent influenza vaccine was not superior to standard-dose quadrivalent vaccine for reducing these events in patients with high-risk cardiovascular (CV) disease in the Influenza Vaccine to Effectively Stop Cardio Thoracic Events and Decompensated Heart Failure (INVESTED) trial.

Objective

To evaluate whether high-dose trivalent influenza vaccination is associated with benefit over standard-dose quadrivalent vaccination in reducing CP events during periods of high, local influenza activity.

Design, Setting, and Participants

This study was a prespecified secondary analysis of INVESTED, a multicenter, double-blind, active comparator randomized clinical trial conducted over 3 consecutive influenza seasons from September 2016 to July 2019. Follow-up was completed in July 2019, and data were analyzed from September 21, 2016, to July 31, 2019. Weekly Centers for Disease Control and Prevention (CDC)-reported, state-level ILI activity was ascertained to assess the weekly odds of the primary outcome. The study population included 3094 patients with high-risk CV disease from participating centers in the US.

Intervention

Participants were randomized to high-dose trivalent or standard-dose quadrivalent influenza vaccine and revaccinated for up to 3 seasons.

Main Outcomes and Measures

The primary outcome was the time to composite of all-cause death or CP hospitalization within each season. Additional measures included weekly CDC-reported ILI activity data by state.

Results

Among 3094 participants (mean [SD] age, 65 [12] years; 2309 male [75%]), we analyzed 129 285 person-weeks of enrollment, including 1396 composite primary outcome events (1278 CP hospitalization, 118 deaths). A 1% ILI increase in the prior week was associated with an increased risk in the primary outcome (odds ratio [OR], 1.14; 95% CI, 1.07-1.21; P < .001), CP hospitalization (OR, 1.13; 95% CI, 1.06-1.21; P < .001), and CV hospitalization (OR, 1.12; 95% CI, 1.04-1.19; P = .001), after adjusting for state, demographic characteristics, enrollment strata, and CV risk factors. Increased ILI activity was not associated with all-cause death (OR, 1.00; 95% CI, 0.88-1.13; P > .99). High-dose compared with standard-dose vaccine did not significantly reduce the primary outcome, even when the analysis was restricted to weeks of high ILI activity (OR, 0.88; 95% CI, 0.65-1.20; P = .43). Traditionally warmer months in the US were associated with lower CV risk independent of local ILI activity.

Conclusions and Relevance

In this secondary analysis of a randomized clinical trial, ILI activity was temporally associated with increased CP events in patients with high-risk CV disease, and a higher influenza vaccine dose did not significantly reduce temporal CV risk. Other seasonal factors may play a role in the coincident high rates of ILI and CV events.

Trial Registration

ClinicalTrials.gov Identifier: NCT02787044.

The Influence of Influenza Virus Infections in Patients with Chronic Obstructive Pulmonary Disease

Introduction

Chronic obstructive pulmonary disease (COPD) is a common disease and is preventable and treatable. A previous study showed that influenza virus infections were also associated with the risk of acute exacerbation in patients with COPD, and other studies showed that the influenza virus might increase the risk of stroke. However, studies on the influence of influenza infection among COPD patients are limited. In this study, we review the role of influenza infection in contributing to mortality, pneumonia, respiratory failure, COPD acute exacerbation, and ischemic stroke among COPD patients.

Materials and Methods

We performed a population-based cohort study of COPD patients using data from Taiwan between January 1, 2011, and December 31, 2019. We excluded patients with lung cancer, lung transplantation and asthma. We also excluded patients who lacked COPD medication prescriptions and those treated with anti-influenza drugs without flu diagnosis records. Patients with missing or incomplete data were also excluded from the study cohort.

Results

After 1:1 matching by age, sex, COPD duration, diagnosed years and comorbidities, we enrolled 10,855 cases and controls for further analysis. The risks of pneumonia, respiratory failure, COPD acute exacerbation, and ischemic stroke were 1.770 (95% CI=1.638–1.860; P<0.0001), 1.097 (95% CI=1.008–1.194; P=0.0319), 1.338 (95% CI=1.248–1.435; P<0.0001), and 1.134 (95% CI=1.039–1.239, P=0.0051), respectively, in the influenza infection group compared with COPD patients without influenza infection.

Conclusion

Influenza infections are linked to an increased risk of ischemic stroke, pneumonia, respiratory failure, and COPD acute exacerbation among COPD patients. In conclusion, patients with COPD need to be closely monitored after having an influenza infection.

Cardioprotective effects of Influenza Vaccination among Patients with Established Cardiovascular Disease or at High Cardiovascular Risk: A Systematic Review and Meta-analysis

BACKGROUND

The clinical impact of the influenza vaccination on cardiovascular outcomes in people with established cardiovascular disease (CVD) is still debated.

AIM

The aim of this meta-analysis was to estimate the effect of influenza vaccination on cardiovascular and cerebrovascular outcomes among patients with established CVD.

METHODS

We systematically searched all electronic databases from inception until 15 April 2022. Primary clinical outcomes were all-cause mortality (ACM), and major adverse clinical events (MACE). Secondary endpoints were heart failure, myocardial infarction, CV mortality, and stroke.

RESULTS

Eighteen articles (five randomized trials and thirteen observational studies), with a total of 22,532,165 patients were included in the analysis. There were 217,072 participants included in the high cardiovascular risk or established CVD population (vaccinated n = 111,073 and unvaccinated n = 105,999). The mean age of the patients was 68 years old, without any difference between groups (69 vs 71) years. At mean follow-up of 1.5 years, vaccinated group was associated with lower risk for all-cause mortality [HR, 0.71(95%CI, 0.63-0.80), p < 0.001], MACE [HR, 0.83(95%CI:0.72-0.96), p = 0.01], CV mortality [HR, 0.78(95%CI:0.68-0.90), p < 0.001] and myocardial infarction [HR, 0.82(95%CI:0.74-0.92), p < 0.001] compared to unvaccinated group. While incidence of stroke [HR, 1.03 (95%CI, 0.92-1.06), p = 0.61] and heart failure [HR, 0.74 (95%CI, 0.51-1.08), p = 0.12] did not differ between the two groups.

CONCLUSION

Influenza vaccination reduced major adverse clinical events, all-cause mortality, CV mortality and myocardial infarction. These highlighted the importance of influenza vaccination in established CVD or high cardiovascular risk.

Individual and Joint Effects of Influenza-Like Illness and Vaccinations on Stroke in the Young: A Case-Control Study

BACKGROUND:

Influenza-like illness (ILI) is an acute trigger for stroke, although joint effects of vaccinations and ILI have not yet been explored.

METHODS:

Data for our case-control study was obtained from MarketScan Commercial Claims and Encounters between 2008 and 2014. Patients 18 to 65 years old who experienced a stroke were matched on age and admission date to a control, defined as patients with head trauma or ankle sprain at an inpatient or emergency department visit. Exposures were ILI in the prior 30 days, and any type of vaccination during the year prior. Our outcome was ischemic and intracerebral hemorrhagic strokes identified using International Classification of Diseases, Ninth Revision (ICD-9 ) codes. Logistic regression models estimated adjusted odds ratios (aORs) controlling for preventive care visits, diabetes, valvular heart disease, smoking, alcohol abuse, obesity, and hypertension.

RESULTS:

We identified and matched 24 103 cases 18 to 44 years old and 141 811 45 to 65 years old. Those aged 18 to 44 years had increased stroke risk 30 days after ILI (aOR, 1.68 [95% CI, 1.51–1.86]) and reduced risk with any vaccination in the year prior (aOR, 0.92 [95% CI, 0.87–0.99]). Joint effects indicate that ILI was associated with increased stroke risk among those with (aOR, 1.41 [95% CI, 1.08–1.85]) and without (aOR, 1.73 [95% CI, 1.55–1.94]) vaccinations in the prior year ( P interaction =0.16). Among those aged 45 to 65 years, adjusted analyses indicate increased stroke risk for those with ILI (aOR, 1.32 [95% CI, 1.26–1.38]), although there was no effect of vaccinations (aOR, 1.00 [95% CI, 0.97–1.02]). Joint effects indicate that ILI was not associated with stroke among those with any vaccination (aOR, 1.07 [95% CI, 0.96–1.18]) but was associated with increased risk among those without vaccinations ([aOR, 1.39 [95% CI, 1.32–1.47]; P interaction <0.001).

CONCLUSIONS:

ILI was associated with increased stroke risk in the young and middle-aged, while vaccinations of any type were associated with decreased risk among the young. Joint effects of ILI and vaccinations indicate vaccinations can reduce the effect of ILI on stroke.

Burden of influenza in patients with cardiovascular disease who receive antiviral treatment for influenza

AIMS

Cardiovascular disease (CVD) increases the risk of complications from respiratory viruses, including influenza. Moreover, respiratory viruses may increase the risk of CV events. Antiviral medication may reduce healthcare resource utilization (HRU), but more data is needed in CVD populations to explore relationships between influenza antiviral treatment, CVD-related complications, HRU, and costs.

MATERIALS AND METHODS

This retrospective claims analysis examined data extracted from IBM MarketScan Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits databases during three influenza seasons: 2016-2017, 2017-2018, or 2018-2019. Propensity score matching was used to compare HRU outcomes and costs among CVD patients treated with influenza antivirals and untreated patients.

RESULTS

Across all influenza seasons, patients with CVD and influenza who received antiviral treatment had fewer all-cause emergency department (ED) visits (p < .01), respiratory-related HRU (p < .01), respiratory-related outpatient and ED visits (both p < .01), CVD-related HRU (p < .01), heart failure-related HRU visits (p < .01), and kidney failure-related HRU (p < .01) 180 days post-treatment fill date than CVD patients untreated for influenza. CVD patients treated with antivirals also had a lower mean number of all-cause inpatient, outpatient, and ED visits and days of stay (all p < .01) and fewer mean respiratory-related outpatient and ED visits (both p < .01). HRU patterns were generally consistent over time and across individual influenza seasons. Finally, treated CVD patients incurred lower all-cause outpatient costs 180 days post-treatment fill date (p < .05) than CVD patients untreated for influenza.

CONCLUSION

CVD patients who contract influenza and take antiviral medication have fewer short- and long-term influenza-related complications and less overall HRU compared with CVD patients who were not prescribed antiviral treatments. Antiviral treatment may be an important tool in reducing complications in CVD patients with influenza.

Association of the COVID-19 Outbreak with Acute Stroke Care in Switzerland

Background and purpose

In Switzerland, the COVID‐19 incidence during the first pandemic wave was high. Our aim was to assess the association of the outbreak with acute stroke care in Switzerland in spring 2020.

Methods

This was a retrospective analysis based on the Swiss Stroke Registry, which includes consecutive patients with acute cerebrovascular events admitted to Swiss Stroke Units and Stroke Centers. A linear model was fitted to the weekly admission from 2018 and 2019 and was used to quantify deviations from the expected weekly admissions from 13 March to 26 April 2020 (the “lockdown period”). Characteristics and 3‐month outcome of patients admitted during the lockdown period were compared with patients admitted during the same calendar period of 2018 and 2019.

Results

In all, 28,310 patients admitted between 1 January 2018 and 26 April 2020 were included. Of these, 4491 (15.9%) were admitted in the periods March 13–April 26 of the years 2018–2020. During the lockdown in 2020, the weekly admissions dropped by up to 22% compared to rates expected from 2018 and 2019. During three consecutive weeks, weekly admissions fell below the 5% quantile (likelihood 0.38%). The proportion of intracerebral hemorrhage amongst all registered admissions increased from 7.1% to 9.3% (p = 0.006), and numerically less severe strokes were observed (median National Institutes of Health Stroke Scale from 3 to 2, p = 0.07).

Conclusions

Admissions and clinical severity of acute cerebrovascular events decreased substantially during the lockdown in Switzerland. Delivery and quality of acute stroke care were maintained.