Risk of death during the 2020 UK COVID-19 epidemic among people with rare autoimmune diseases compared to the general population. Preliminary results from the RECORDER project.

Peach, E. J.; Rutter, M.; Lanyon, P. C.; Grainge, M. J.; Hubbard, R. B.; Aston, J.; Bythell, M.; Stevens, S.; Pearce, F. A.

Objectives: To quantify the risk of death among people with rare autoimmune rheumatic diseases (RAIRD) during the UK 2020 COVID-19 epidemic compared with baseline risk and the risk of death in the general population during COVID-19. Design A cohort study using data from the National Congenital Anomaly and Rare Disease Registration Service (NCARDRS). We used ONS published data for general population mortality rates. Setting: Hospital Episode Statistics for England 2003 onwards, and linked data from the NHS Personal Demographics Service. Participants: 168,691 people with RAIRD who were alive on 1 March 2020. Their median age was 61.7 (IQR 41.5-75.4) years, and 118,379 (70.2%) were female. Our case ascertainment methods had a positive predictive value >85%. Main outcome measure: Age-standardised mortality rates for all-cause death. Secondary outcome measures were age-sex standardised mortality rates, and age-stratified mortality rates. Results: 1,815 (1.1%) participants died during March and April 2020. The age-standardised mortality rate (ASMR) among people with RAIRD (3669.3, 95% CI 3500.4-3838.1 per 100,000 person-years) was 1.44 (95% CI 1.42-1.45) times higher than the average ASMR during the same months of the previous 5 years, whereas in the general population of England it was 1.38 times higher. Compared to the general population, the age-specific mortality rates in people with RAIRD compared to the pre-COVID rates were higher from the age of 35 upwards, whereas in the general population the increased risk began from age 55 upwards. Sex-specific rates were similar in males and females, whereas in the general population females had a lower rate than males. Conclusions: The risk of all-cause death is more prominently raised during COVID-19 among people with RAIRD than among the general population. We urgently need to quantify how much risk is due to COVID-19 infection and how much is due to disruption to healthcare services, in order to inform better guidance about shielding, access to healthcare and vaccine priorities for people with rare diseases.