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Take a look at a selection of our recent media coverage:
9th January 2023
Infection with herpes zoster is associated with a higher long‐term risk of a major cardiovascular event such as a stroke and the development of coronary heart disease, according to an analysis of three large, prospective studies by researchers from Harvard Medical School, Boston, US.
Herpes zoster (HZ) occurs after reactivation of the varicella-zoster virus which is both persistent and clinically dormant, within spinal ganglia or cranial sensory nerves following an initial infection with varicella. In fact, HZ strikes millions of older adults annually worldwide and disables a substantial number of them via post-herpetic neuralgia. Moreover, in recent years, emerging evidence suggests that HZ infection leads to 1.3 to 4-fold increased risk of cerebrovascular events with a higher risk among adults under 40 years of age and within one year after an HZ episode. However, what remains unclear, is the long‐term association between HZ infection and the risk of adverse cardiovascular events or cardiovascular disease.
In the present study, US researchers investigated the longitudinal association of herpes zoster (or ‘shingles’) and the risk of stroke or coronary heart disease (CHD) among participants in 3 large US cohorts; the NHS (Nurses’ Health Study), NHS II (Nurses’ Health Study II), and HPFS (Health Professionals Follow-Up Study). Within the three cohorts, participants were asked to self-report about clinician‐diagnosed shingles and the year of diagnosis. The primary exposure for the study was categorised according to time (in years) since the participant’s HZ event and those with no history of HZ served as the reference group. The researchers then categorised the time since HZ as never, 1 to 4 years since infection, 5 to 8 years, 9 to 12 years and ≥13 years. In their analysis, adjustment were made for several factors that could potentially be related to HZ and stroke or CHD, including age, race, smoking history, body mass index, waist circumference etc.
Herpes zoster infection and cardiovascular events
The study included data on 79,658 women in the NHS, 93,932 in the NHS II and 31,440 men in the HPFS (2004-2016), without prior stroke or CHD. During >2 million person-years of follow-up, 3603 incident stroke and 8620 incident CHD cases were documented.
In a pooled analyses and compared to those without a history of HZ infection, the multivariable-adjusted hazard ratio (HR) for stroke was non-significant for those with 1 to 4 years since HZ infection (HR = 1.05, 95% CI 0.88 – 1.25). However, the associations became significant as the duration from infection increased. For example, among those with 5 to 8 years since HZ, the hazard ratio was 1.38 (95% CI 1.10 – 1.74) and 1.28 (95% CI 1.03 – 1.59) among those with for 9 to 12 years since HZ. Interestingly, the association became non-significant among those with ≥13 years since HZ (HR = 1.19, 95% CI 0.90 – 1.56).
When considering CHD, the corresponding multivariable-adjusted hazard ratios were similar, e.g. 1.25 (95% CI 1.07 – 1.46) for 9 to 12 years and, as with stroke, the risk of CHD became non-significant after ≥13 years (HR = 1.00, 95% CI 0.83 – 1.21).
The authors concluded that herpes zoster is associated with a higher long-term risk of a major cardiovascular event, underscoring the importance of prevention of infection.
Curhan SG et al. Herpes Zoster and Long-Term Risk of Cardiovascular Disease. J Am Heart Assoc. 2022
8th December 2022
Individuals with higher levels of morning physical activity have the lowest risk of incident cardiovascular disease and stroke compared to those who have a midday peak pattern according to an analysis by Dutch researchers.
Cardiovascular diseases (CVD) are the leading cause of global mortality with an estimated 17.9 million lives lost each year. One modifiable factor linked to CVD is physical activity (PA) and data suggests that PA is not only associated with lower risk for of CVD but that the greatest benefit is seen for those who engage in higher levels of activity. However, emerging evidence suggests that the timing of PA may also be an important and influential factor. For example, in a study of more than 7,000 women, researchers found that women who are less active during morning hours may be at higher risk of obesity. In addition, an exercise-based trial which considered the impact of exercise timing on weight loss, showed that morning physical activity led to a significantly higher weight loss compared to evening activity. But mornings might not always be best as a study in men with type 2 diabetes observed that those who undertook high intensity interval training (HIIT) in an afternoon compared to morning session, had better glucose control.
In trying to better understand the impact of the timing of physical activity on the risk of incident CVD, the Dutch researchers collected physical activity data from participants in the UK-Biobank through triaxial accelerometer over a 7-day period which collected 24-hour mean activity levels. The team then used this data to create four different clusters of physical activity: cluster 1 represented the average pattern among the total biobank population which peaked around midday; cluster 2 were those with an early morning peak; cluster 3 a late morning peak and cluster 4, those with an evening peak. Regression analysis was used based on two models, the first (model 1) was adjusted for age and gender, and the second (model 2) additionally adjusted for body mass index and smoking status.
Morning physical activity and cardiovascular outcomes
A total of 86,657 individuals with a mean age of 61.6 years (58% female) were included and followed for 6 years during which time there were 2,911 cases of incident CVD and 796 strokes.
In an analysis based on model 1, participants who had higher levels of morning or later morning (clusters 2 and 3) physical activity, had a 11% (hazard ratio, HR = 0.89, 95% CI 0.80 – 0.99) and 16% (HR = 0.84, 95% CI 0.77 – 0.92) respectively, lower incidence of incident CVD compared to those in cluster 1. However, only those in cluster 3 (late morning physical activity) had a significantly reduced risk of stroke (HR = 0.83, 95% CI 0.70 – 0.98) and ischaemic stroke (HR = 0.79, 95% CI 0.64 – 0.97). Interestingly, when the researchers used model 2, the benefits were no longer statistically significant apart from a reduced risk of ischaemic stroke for those in cluster 3 (HR = 0.73, 95% CI 0.57 – 0.94).
In subgroup analysis based on gender and using model 2, there were statistically significant reductions in the risk of incident CVD but only among women who were either early and later morning exercisers. In addition, the risk of ischaemic stroke was only significantly lower among women in cluster 3 (HR = 0.56, 95% CI 0.38 – 0.83). When stratifying by participant levels of activity (i.e., either less or more active) and using model 2, although there were reductions in the risk of both CVD and stroke, among those who were more active, these reductions were non-significant.
The authors concluded that morning physical activity was associated with lower risks of incident cardiovascular diseases and that these findings highlighted the potential importance of chrono-activity in CVD prevention.
Albalak G et al. Setting your clock: associations between timing of objective physical activity and cardiovascular disease risk in the general population. Eur J Prev Cardiol 2022
9th August 2022
COVID-19 vaccination provides individuals with a reduced risk of experiencing an acute myocardial infarction or ischaemic stroke after becoming infected with the virus according to the findings of a study by Korean researchers.
It has now become recognised that following an acute infection with COVID-19, beyond the first 30 days, individuals with COVID-19 have an increased risk of cardiovascular disease and which includes cerebrovascular disorders, dysrhythmias, ischaemic and non-ischaemic heart disease, pericarditis, myocarditis, heart failure and thromboembolic disease. While it is clear that a COVID-19 vaccination is safe and offers protection against severe COVID-19, hospitalisation and death against all current variants of concern, what is less clear is whether vaccination is able to reduce the post-infection cardiovascular sequelae. As a result, for the present study, the Korean researchers undertook a retrospective cohort study and compared the incidence of acute myocardial infarction and ischaemic stroke in those with and without full COVID-19 vaccination. They linked data from the Korean nationwide COVID-19 registry and the National Health Insurance database and included all adults who were diagnosed with COVID-19 between July 2020 and December 2021. However, the team excluded several patient groups including: individuals whose data showed that they had a cardiovascular event three months before a COVID-19 infection, cases of re-infection with the virus and patients who were vaccinated but hospitalised with the virus for longer than 30 days. They set the primary outcome of interest as a composite of all hospitalisations for an acute myocardial infarction and ischaemic stroke and which had occurred 31 to 120 days after an individual’s COVID-19 diagnosis. They decided to exclude cardiovascular events within the first 30 days of infection because of the inherent difficulty of differentiating whether the event was related to infection of treatment.
COVID-19 vaccination and cardiovascular outcomes
A total of 231,037 patients were included in the analysis, of whom, 62,727 were unvaccinated and with a median age of 42 years (51.5% female). The median age of the vaccinated group was higher (57 years) and had a greater incidence of co-morbidities including diabetes (11.8% vs 7.1%, vaccinated vs unvaccinated) and hypertension (22.1% vs 10.8%). Furthermore, a higher proportion of unvaccinated individuals had severe COVID-19 (3.1% vs 9.8%). The median period of follow-up was 90 days in the unvaccinated and 84 days in the fully vaccinated group (which was defined as receipt of 2 doses of a vaccine).
The composite outcome occurred in 31 unvaccinated individuals and 74 of those who were fully vaccinated and after adjustment for differences in baseline characteristics, this difference was statistically significant (hazard ratio, HR = 0.42, 95% CI -.29 – 0.62, p < 0.001). This difference was also significant for the individual components of the composite.
The authors concluded that full COVID-19 vaccination was protective against the acute myocardial infarction and an ischaemic stroke that could arise after infection with the virus, compared with individuals who were unvaccinated.
Kim YE et al. Association Between Vaccination and Acute Myocardial Infarction and Ischemic Stroke After COVID-19 Infection JAMA 2022
10th January 2022
The subsequent stroke risk among those who experience a transient ischaemic attack (TIA) is higher in patients seen at an emergency department compared to those seen at a rapid-access TIA clinic according to a meta-analysis by a team from the Neurology Department, Neuroscience Institute, Geisinger Health System, Pennsylvania, US.
After a TIA, the ischaemic stroke risk can range from 2.4% within 2 days to 4.7% within 90 days although the authors of this study hint that this risk may have reduced in the last two decades. Although patients with a suspected stroke might normally visit a hospital, the availability of 24-hour TIA clinics with immediate initiation of preventive treatment, have the potential to greatly reduce length of hospital stay.
Despite the presence of TIA clinics there is currently little is known about the outcomes for those experiencing a TIA who have been treated in different care settings. For the present study, the US team performed a meta-analysis to estimate and compare the risk of a subsequent ischaemic stroke in those with a TIA or minor ischaemic stroke (mIS) who received their care at either a rapid access TIA clinic, an inpatient unit, emergency departments (EDs) or other settings. The researchers focused on the subsequent stroke risk after 4 defined time periods; 2, 7, 30 and 90 days. Their literature search covered medline, Embase, CINAHL and clinical trial databases for studies that provided information on the occurrence of an ischaemic stroke after a TIA or mIS and included both retrospective and prospective studies. The primary outcome of the study was the proportion of early ischaemic strokes after the index TIA or mIS among patients receiving care in the four different settings and they focused their comparison on a TIA clinic vs inpatient facilities.
A total of 71 studies were included in the final analysis with 226,683 patients, 5636 from a TIA clinic, 130,136 inpatients, 3605 emergency department patient and 87,303 from a unspecified centre. The mean age of patients ranged from 65.7 to 78.3 years and proportion of male patients from 38.4% to 52.4%.
The stroke risk after a TIA or mIS at a TIA clinic was 0.3% within 2 days, 1% within 7 days, 1.3% after 30 days and 2.1% after 90 days. The highest risk was for patients treated at unspecified settings and which ranged from 2.2 % within 2 days to 6% within 90 days. When comparing the stroke risk between a TIA clinic or inpatient facility, there was no significant difference in any of the 4 time intervals. However, the risks were significantly higher among those receiving emergency department care compared to a TIA clinic within 2, 7 and 90 days.
The authors concluded that the risk of subsequent stroke among patients who were evaluated in a TIA clinic was not higher than among those hospitalised adding that patients treated in an emergency department without further follow-up had a higher risk of subsequent stroke.
Shahjouei S et al. Risk of Subsequent Stroke Among Patients Receiving Outpatient vs Inpatient Care for Transient Ischemic Attack: A Systematic Review and Meta-analysis JAMA Netw Open 2022