Covid-19 positive outpatients are at an increased risk of neurodegenerative disorders compared with individuals who tested negative for the virus, finds a new study.The study, presented at the 8th European Academy of Neurology (EAN) Congress, found that those who had tested positive for Covid-19 were at an increased risk of Alzheimer's disease, Parkinson's disease, and ischaemic stroke.
"We found support for an increased risk of being diagnosed with neurodegenerative and cerebrovascular disorders in Covid-19 positive compared to Covid-negative patients, which must be confirmed or refuted by large registry studies in the near future," said lead author Pardis Zarifkar from Rigshospitalet hospital in Denmark.
"Reassuringly, apart for ischemic stroke, most neurological disorders do not appear to be more frequent after Covid-19 than after influenza or community-acquired bacterial pneumonia," Zarifkar added.Out of the 919,731 individuals who tested for Covid-19 within the study, researchers found that the 43,375 people who tested positive had a 3.5 times increased risk of being diagnosed with Alzheimer's disease.
They also found 2.6 times increased risk of being diagnosed with Parkinson's disease, 2.7 times with ischaemic stroke and 4.8 times increased with intracerebral haemorrhage (bleeding in the brain).While neuroinflammation may contribute to the accelerated development of neurodegenerative disorders, the authors also highlighted the implications of the scientific focus on long-term sequelae after Covid-19.
The study analysed in-and outpatients between February 2020 and November 2021, as well as influenza patients from the corresponding pre-pandemic period.The team used statistical techniques to calculate relative risk, and results were stratified for hospitalisation status, age, sex, and co-morbidities.