Every infection type was linked with an increased likelihood of ischaemic stroke, with the strongest link seen with urinary tract infection (UTI), which showed more than three times the increased risk within 30 days of infection, found a large US analysis.
Previous research examined infections as triggers of stroke, but were limited to the correlation of acute infections with ischaemic stroke, a type of stroke caused by blocked blood vessels in the brain. This study considered a wider range of infections, and examined connections with two other types of stroke: intracerebral haemorrhage, which is caused by a ruptured blood vessel in the brain, and a type of stroke that results from bleeds in the inner lining of the brain, called subarachnoid haemorrhage.
“Healthcare providers need to be aware that stroke can be triggered by infections,” said Dr Mandip Dhamoon, senior study author and associate professor of neurology at the Icahn School of Medicine at Mount Sinai in New York City. “Probing into the previous weeks or months of a patient’s life before the stroke can sometimes help to illuminate the possible causes of stroke if there was an infection during that time.”
The researchers used the New York State Inpatient Databases and Emergency Department Databases from 2006 to 2013, which record all inpatient and emergency department visits to community hospitals in New York state. Electronic health record codes were used to identify hospitalisations and emergency department visits for the three types of stroke and for infections; including skin, urinary tract, septicaemia, abdominal and respiratory. Records for hospitalisations for infections were considered for 7, 14, 30, 60, 90, and 120 days prior to the stroke occurrence.
For ischaemic stroke, the researchers found that every infection type was linked with an increased likelihood of this type of stroke. The strongest link was seen with urinary tract infection, which was showed more than three times the increased risk of ischemic stroke within 30 days of infection. For all infection types, the magnitude of stroke risk decreased as the time period before ischemic stroke occurred increased.
For intracerebral haemmorhage, the connections with occurrence was strongest for urinary tract infections, septicaemia (blood infection) and respiratory infections. Respiratory infection was the only infection related to the occurrence of subarachnoid haemorrhage.
“Our study shows that we need to do more to understand why and how infections are associated with the occurrence of different kinds of stroke, and that will help us to determine what we can do to prevent these types of strokes,” Dhamoon said. “These findings suggest that there could be implications for vaccination, antibiotic regimens or intensive antithrombotic treatments not only to prevent the infections but to prevent stroke in those who are deemed high-risk.”
Background and Purpose: The relationships between different infection types and stroke subtype are not well-characterized. We examined exposure to infections in different organ systems in different time periods before the acute ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage.
Methods: We used the New York State Inpatient Databases and Emergency Department Databases (2006–2013). Validated International Classification of Diseases, Ninth Edition definitions identified index hospitalizations for acute ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, and emergency department visits and hospitalizations for infection (skin, urinary tract infection, septicemia, abdominal, and respiratory). We used case cross-over analysis with conditional logistic regression to estimate odds ratios (OR) for the association between each infection type during case periods compared with control periods 1 year before.
Results: Every infection type was associated with an increased likelihood of acute ischemic stroke. The greatest association was for urinary tract infection, with OR of 5.32 (95% CI, 3.69–7.68) within the 7-day window. The magnitude of association between urinary tract infection and intracerebral hemorrhage was of lesser magnitude, with OR of 1.80 (1.04–3.11) in the 14-day exposure period and OR of 1.54 (1.23–1.94) in the 120-day exposure period. Only respiratory infection was associated with subarachnoid hemorrhage, with OR of 3.67 (1.49–9.04) in the 14-day window and 1.95 (1.44–2.64) in the 120-day window.
Conclusions: All infection types were associated with subsequent acute ischaemic stroke, with the greatest association for urinary tract infection.
Solly Sebastian, Laura K Stein, Mandip S Dhamoon