Authors: Sharon Salt (Editor)
Find out more about the headlines from the International Stroke Conference (ISC; 6–8 February 2019, Honolulu, HI, USA) below, which features preliminary research and top abstracts from the conference. Highlights include:
Pregnancy and delivery
- Infection during delivery linked to greater risk of stroke after delivery
- Pregnancy-related stroke more common among black women
Infections and gut microbes
- Treating shingles after it appears doesn’t reduce increased stroke risk
- Opioid epidemic fuelling a rise in infection-related stroke
E-cigarettes and pollution
- E-cigarettes linked to higher risk of stroke, heart attack, diseased arteries
- Higher rates of stroke deaths in countries with dirtier air
Infection during delivery linked to greater risk of stroke after delivery
According to preliminary research to be presented at ISC 2019, women diagnosed with an infection during delivery had a much greater risk of stroke after their delivery.
Researchers examined more than 3.5 million delivery hospitalizations from the 2013 Healthcare Cost and Utilization Project National Readmissions Database, which compiles information on hospital care throughout the USA. Out of 79,656 women who were readmitted to the hospital within 1 month after delivery, 225 were readmitted for stroke.
Reporting on their findings, the researchers revealed a strong relationship between infections (e.g., bladder infections, pneumonia and sepsis) during hospitalization for delivery and stroke within the following months. They also indicated that women with an infection during delivery hospitalization were more than five-times as likely to be readmitted to the hospital for stroke. Lastly, women readmitted for stroke were more than three-times as likely to have had an infection during their delivery hospitalization, compared with women readmitted for other reasons.
Eliza Miller (Columbia University Irving Medical Center, NY, USA), lead author of the study, cautioned that: “…the number of stroke readmissions was small, so it’s important not to draw the conclusion that everyone who has an infection is going to have a stroke. The study shows an association but does not prove that the infection caused the stroke.”
Pregnancy-related stroke more common among black women
The risk of pregnancy-related stroke is much higher among black women than among white women, according to preliminary research to be presented at ISC 2019.
Stroke is the fifth-leading cause of death and a major cause of long-term disability in the USA. Women are more likely to have a stroke than men and to die as a result, and pregnancy increases the risk.
To find out if stroke risk differs by race during and after delivery, researcher studied records from the Nationwide Inpatient Sample, which is a publicly available database of hospitalizations from 1998 to 2014. These records comprised nearly 68 million delivery hospitalizations and 1.1 million post-delivery hospitalizations for women between 15- to 54-years-old.
Of the nearly 68 million delivery hospitalizations, 8241 women were diagnosed with stroke during delivery. Of the 1.1 million hospitalizations after delivery, 11,073 women were readmitted for stroke.
After studying the deliveries, the investigators revealed that black women were at 64% higher risk for stroke during delivery and 66% higher risk for stroke during postpartum admissions than white women. In addition to this, black and Hispanic women with pregnancy-related high blood pressure, such as preeclampsia, were twice as likely as white women to have a stroke during delivery. However, postpartum stroke hospitalizations for Hispanic women did not differ from white women.
“Further research is needed to better understand if these high-risk groups would benefit from a more aggressive blood pressure control. It is also important to carefully look at all of the modifiable risk factors that could help prevent stroke in these groups,” concluded Maria Daniela Zambrano (Columbia University), lead author of the study.
Treating shingles after it appears doesn’t reduce increased stroke risk
In preliminary research to be presented at ISC 2019, researchers have demonstrated that stroke risk increased significantly in the days, weeks and months after shingles appears, despite use of the shingles vaccine and antiviral therapy to treat it.
Investigators from the Centers for Disease Control and Prevention studied more than 35,000 Medicare fee-for-service beneficiaries who had been diagnosed with shingles and acute ischemic stroke between 2007 and 2015. They analysed whether having the shingles vaccine, Zostavax®, as treatment, antiviral therapy or both after shingles would impact patients’ stroke risk.
They revealed that stroke incidence jumped by 61% within 14 days after the onset of shingles. The increased stroke risk remained elevated 6 months after shingles but diminished with time.
Researchers didn’t find any evidence that having the vaccine or taking antiviral therapy once shingles appeared helped to reduce the increased stroke risk. But the researchers suggest having the shingles vaccine might be the most effective way to prevent shingles-associated stroke risk.
Opioid epidemic fueling a rise in infection-related stroke
Preliminary research has indicated that the opioid epidemic is fueling a steep rise in infection-related stroke hospitalizations. The results of this study will be presented at ISC 2019.
Injecting opioids, such as heroin, can introduce bacteria into the body which travel through the bloodstream to infect and inflame heart vessels, a condition called infective endocarditis.
Infective endocarditis can lead to stroke if clumps of the infected tissue break off and travel to the brain’s blood vessels and block them. This is the first study to examine trends in the incidence of stroke as a complication of opioid-related heart infection.
Using a national hospital inpatient database, researchers identified residents in the USA who were hospitalized in 1993 through 2015, with the combination of opioid abuse, infective endocarditis and any type of stroke.
They revealed that 5283 patients were hospitalized with stroke from opioid-related infective endocarditis, and that hospitalizations for stroke from opioid-related infective endocarditis increased from 2.4/10 million people in 1993 to 18.8/10 million people in 2015.
Additionally, they reported that there was no significant increase in the rate of stroke hospitalization between 1993 and 2008, but between 2008 and 2015, the rate of stroke hospitalizations significantly increased by 20% per year, coinciding with the worsening of the opioid epidemic.
“The rise in hospitalizations for infective endocarditis-related stroke associated with opioids parallels the rise in heroin overdose-related complications and deaths, which tripled between 2010 and 2015,” commented Setareh Salehi Omran (Columbia University Medical Center), lead author of the study.
E-cigarettes linked to higher risk of stroke, heart attack, diseased arteries
Using e-cigarettes increases your odds of having a stroke, heart attack and coronary heart disease, according to preliminary research to be presented at ISC 2019.
In the largest study to date examining e-cigarettes and stroke, researchers tapped a database of 400,000 respondents, the 2016 behavioral risk factor surveillance system (BRFSS). With this, the investigators collected data from residents in all 50 states in the USA about their health-related risk behaviors, chronic health conditions and use of preventive services.
Approximately 66,795 respondents reported regularly using e-cigarettes, whereas the control group included 343,856 respondents who reported having never used e-cigarettes. Odds ratios were calculated using logistic regression analysis.
Researchers found that compared with non-users, e-cigarette users had 71% higher risk of stroke, 59% higher risk of heart attack or angina and 40% higher risk of coronary heart disease.
They also found that 4.2% of e-cigarette users reported having suffered a stroke. However, the study data did not show deaths attributable to e-cigarette use.
Higher rates of stroke deaths in countries with dirtier air
In a nationwide study, countries with dirtier air had higher rates of stroke deaths and shorter life expectancies, according to preliminary data to be presented at ISC 2019.
The average yearly levels of air pollution (PM2.5) that contain fine inhalable particles were examined by researchers. Produced by diesel engines and the burning of coal, biomass and kerosene, this type of air pollution has previously been shown to enter the circulatory system and harm health.
Analyzing health data and pollution monitoring information from 1561 counties across the USA between 2005 and 2019, researchers found the yearly average for fine air pollution ranged from 7.2 to 14.7 (average 11.75) μg per cubic meter.
“Overall, the annual average was at a level considered acceptable. However, 51% of counties had an annual average exceeding 12 μg per cubic meter, the annual average limit of the National Air Quality Standards for PM2.5 set by the Environmental Protection Agency (December 2012),” explained Longjian Liu (Drexel University, PA, USA), lead author of the study.
When examining associations between county average PM2.5 pollution levels and health measured (age-adjusted rates in adults 35 years and older), the researchers found that the dirtier the air, the higher the rate of stroke deaths and shorter life expectancy in both men and women.
Additionally, the researchers reported that the highest impact on stroke was in the south. The new results raise the possibility that exposure to PM2.5 pollution may be a factor in creating the so-called ‘stroke belt’ in southern USA. Other possible contributors to excessive stroke rates in these states are poverty, diet, smoking, the control of stroke risk factors and the availability of health services.
Stroke risk factors increase among breast cancer survivors
Risk factors for stroke rise sharply in post-menopausal women in the first year after they are diagnosed with breast cancer, according to preliminary research to be presented at ISC 2019.
Cancer is a well-known risk factor for stroke. However, it is unclear if the risk further increases with long-term survival or whether the stage of cancer and receiving hormonal therapy affect stroke risk particularly in post-menopausal breast cancer.
Within the study, researchers examined changes in the Framingham Stroke Risk Score (FSRS) after breast cancer diagnosis among women included in a Virginia cancer registry. Of 2141 eligible women (average age 64 at diagnosis), there was complete information to calculate the five-factor Framingham Stroke Risk in 616 women.
The researchers revealed that the average FSRS was 10.6 at diagnosis, corresponding to a 6% probability of having a stroke in the next 10 years. Moreover, 1 year after diagnosis, FSRS had increased to 16.07, tripling the likelihood of a stroke in the next 10 years (19%). They also noted that tumor stage was not related to changes in stroke risk, and that hormonal treatment was associated with a higher stroke risk score.
“Prevention and control of high blood pressure and diabetes should be a target of intervention to reduce the stroke risk among post-menopausal breast cancer survivors,” concluded Kyungeh An (Virginia Commonwealth University, VA, USA), lead author of the study.