Scientists at Queen Mary University of London analysed data from 53,613 British adults, including 17,871 who caught Covid-19 between March 2020 and March last year. The study found people who were admitted to hospital with Covid were 17.5 times more likely to suffer a stroke within a year than people who avoided it, and even mild cases of the virus were linked to an increased risk of developing blood clots and a tenfold increased risk of early death from any cause.
Prior to this study, emerging evidence has suggested that people with previous Covid infections have higher risk of subsequent adverse cardiovascular outcomes. However, these studies are mostly retrospective and include only a limited selection of outcomes, while also not considering variation of risk by severity of Covid.
This new research, published in the British Medical Journal (BMJ), analysed 17, 871 UK Biobank participants and demonstrated association of past Covid infection with increased incidence of a wide range of cardiovascular disease and mortality events. These risks were “almost entirely confined to those requiring hospitalisation and were highest in the first 30 days postinfection”, the study said.
The participants were tracked for five months on average and monitored for death and heart problems including heart disease, stroke, heart failure and blood clots. This was then compared with the health records of similar adults who did not catch Covid-19.
Research found that rates of heart disease were significantly higher among the group who had caught Covid, especially in the first 30 days of infection and in those who needed hospital treatment. Heart attack rates were also ten times higher in the group admitted to hospital with Covid. The stroke risk was 17.5 times higher and they were 21.5 times as likely to be diagnosed with heart failure.
During the study period, 7.3% of those who caught Covid-19 died, compared with 0.2% of those who did not contract coronavirus.
Why is there an increased risk?
Experts believe that inflammation triggered by Covi leads to a heightened long-term risk of blood clots, which in turn can then cause potentially deadly heart attacks and strokes.
Figures from the Office for National Statistics showed that deaths due to heart problems had surged since the Covid pandemic began and were the main driver of unusually high “excess deaths” this year. In May, the number of deaths in England and Wales caused by an irregular heartbeat were up 39%, which experts said may be due to long-term damage of Covid infections. Researchers said the burden of heart disease caused by Covid was becoming “a dominant public health concern”.
The study hopes to bring greater attention to the management of cardiovascular risk and believes a low threshold for investigations of patients with past Covid hospitalisation are important in the prevention and timely treatment of cardiovascular events.
Future studies are needed to address whether specific interventions are needed to reduce the risk of venous thromboembolism (VTE) - a blood clot that starts in a vein - associated with COVID-19, researchers added.