165. COVID-19 pandemic: outcomes among people with rare autoimmune rheumatic diseases during the second wave.

Background: To calculate the rates of COVID-19 infection and COVID-19-related death among people with rare autoimmune rheumatic diseases (RAIRD) during the second wave of the COVID-19 pandemic in England compared to the general population. Methods: We used Hospital Episode Statistics data from the National Congenital Anomaly and Rare Disease Registration Service (NCARDRS) using their legal permissions (CAG 10-02(d)/2015) to identify all people alive 01 August 2020 with ICD-10 codes for RAIRD from the whole population of England. We used linked national health records (demographic, death certificate, admissions and PCR testing data) to calculate rates of COVID-19 infection and death up to 30 April 2021. Our primary definition of COVID-19-related death was mention of COVID-19 on the death certificate. General population data from Public Health England and the Office for National Statistics were used for comparison. We also describe COVID-19-related hospital admissions and all-cause deaths. Results: We identified a cohort of 168,330 people with RAIRD (70.2% female, median age 61.7 (IQR 41.5 – 75.5)). 9,961 (5.92%) had a positive COVID-19 PCR test, which was similar to the general population (6.13%). The age-standardised infection rate ratio between RAIRD and the general population was 0.99 (95% CI 0.97-1.00). 1,342 (0.8%) people with RAIRD died with COVID-19 on their death certificate and the age-sex-standardised mortality rate for COVID-19-related death was 2.76 (2.63 – 2.89) times higher than in the general population. There was no evidence of an increase in deaths from other causes in the RAIRD population. 4432 (2.6%) people with RAIRD had a hospital admission with an associated diagnostic code for COVID-19 and 387 (0.2%) had an ICU admission with an associated diagnostic code for COVID-19. Conclusions: During the second wave of COVID-19 in England, people with RAIRD had a 2.76x increased risk of COVID-19 related death compared to the general population, confirming the increased risk seen during the first wave of the pandemic. Unlike the first wave, the risk of COVID-19 infection was similar between RAIRD and the general population. There was no evidence of increased risk of death from non-COVID-19 related causes. Disclosures: FP & PCL are recipients of a grant from Vifor Pharma. Preprint: https://www.medrxiv.org/content/10.1101/2021.08.17.21260846v3.ful