A study investigating Covid-19 infection and instances of stroke has concluded that the Asian community is statistically high-risk for developing blood clots, and more severe complications.

It has been widely reported that Covid-19 infection has had an ethnic demographic asymmetry, with many people from the Black, Asian and Minority Ethnic community being disproportionally affected when compared to the white population. Although, this was challenged last month by Government advisor Dr Raghib Ali, and the publication of a departmental report which emphasised socioeconomic factors.

Previous research that has studied the inflammatory response to Covid pneumonia has documented the entailing immune response and increased levels of coagulation proteins, that produces clot prone blood – dubbed sticky blood. Naturally, this sticky blood boosts the risk of stroke and other thromboses.

Rates of ischaemic stroke due to Covid-19

Researchers have found that nearly 1 in 5 of those with Covid-19 infection and who had an ischaemic stroke (a blockage of an artery leading to the brain resulting in diminished oxygen supply) were from the Asian community – more than twice the proportion seen in ischaemic stroke patients without Covid-19.

Additionally, these ischaemic strokes were also more severe, with an average stroke severity score of 8 vs 5, resulting in substantial levels of brain cell necrosis and therefore were more likely to lead to more significant disability and mortality risk.

Dr Richard Perry, the lead study author, said of the study’s findings that: “Our study suggests that COVID-19 has had more impact on strokes in the Asian community than in other ethnic groups.”

However, he stressed that the study’s data could not discount possible socioeconomic causation although he considered it to be unlikely: “Those of Asian descent have only a marginally higher risk than White people [of Covid-19 infection]. We suspect, therefore, that Asian people who contract COVID-19 may have a higher risk of COVID-19-associated stroke than is seen in other ethnic groups.”

The study aimed to obtain a clearer picture of the potential stroke risk of Covid-19, doing this by collecting data for 1,370 strokes among patients between March and July, during the first wave to the pandemic.

Of the hospitals that they studied they found that during this period, there were 86 Covid-19 stroke patients, with 81 or those strokes being ischaemic, while the rest were intracerebral haemorrhages – caused by a burst rather than a blocked blood vessel.

Data showed that the ischaemic strokes were twice as likely to be caused by more than one blocked large blood vessel – and were associated with a more severe disability on discharge with an average disability score of 4 out of 6. Additionally, for 45 ischaemic stroke patients, the timeline of the stroke occurred an average of 6 days after infection, and overall death while in emergency wards were calculated to 20%.

Researchers wrote that: ‘We suggest that COVID-19 may provoke the onset of an ischaemic stroke through a variety of thrombotic [clot forming] and inflammatory mechanisms, promoting generation of thrombus [blood clot] in the heart or large vessels or via small vessel occlusion [blockage].’

‘Our study provides the most compelling evidence yet that COVID-19-associated ischaemic strokes are more severe and more likely to result in severe disability or death, although the outlook is not quite as bleak as previous studies have suggested.’