For the study, published in the journal Rheumatology, the research team looked at the electronic health records of 170,000 people in England with rare autoimmune rheumatic diseases.

During March and April 2020 (the first two months of the Covid-19 pandemic), the team found that 1,815 (1.1 per cent) of people with these diseases died.

"People with rare diseases often have poorer health outcomes generally, so we wanted to find out what impact the Covid-19 pandemic has had," said study co-author Fiona Pearce from the University of Nottingham in the UK.

"From our study, we know that during the early months of the pandemic, people with these diseases were more likely to die than the general population," Pearce added.

The results also showed that the risk of dying during Covid-19 for people with these conditions increased from age 35

According to the researchers, women with rare autoimmune rheumatic diseases had a similar risk of death to men during Covid-19 - whereas usually, their risk of death is lower.

For people of working age with rare autoimmune rheumatic diseases, the risk of dying during Covid-19 was similar to that of someone 20 years older in the general population.

"Our study illustrates the unique ability of collaboration with the National Disease Registration Service to generate findings that can improve health in rare diseases," said Peter Lanyon, Consultant Rheumatologist at Nottingham University Hospitals.

"The next steps in our research are to look at death certificate data and find out why people have died. We'll be examining whether it's due to Covid-19 infection or how much is due to the disruption to healthcare services," Pearce added.