POS0574 POPULATION-BASED ANALYSIS OF THE ASSOCIATION BETWEEN SARS-CoV-2 INFECTION AND INCIDENT AUTOIMMUNE DISEASES

Background: Viral infections, especially from retroviruses, can trigger autoimmune diseases. SARS-CoV-2 infection may increase the subsequent incidence of autoimmune diseases. Objectives: We investigated whether SARS-CoV-2 infection is associated with an increased risk of a range of autoimmune diseases listed in Figure 1. Methods: We conducted a population-based cohort study, using administrative health datasets for the entire province of British Columbia, Canada. Sample: Participants were identified from February 2020 to January 2022, and followed up until December 2022. SARS-CoV-2 infection was confirmed by positive polymerase chain reaction test. SARS-CoV-2-positive patients were matched 1:3 with SARS-CoV-2 test-negative patients on age, sex, health region in British Columbia, and month/year of index date (date of SARS-CoV-2 test). Outcome: One or more ICD-9 or ICD-10 codes in outpatient and/or hospitalization data were used to identify all individuals with 34 autoimmune diseases following the index date. All individuals with at least one ICD code for an autoimmune disease in the seven years prior to the index date were excluded from the analysis for that disease. Cox proportional hazard regression models adjusting for socioeconomic status (neighborhood income quintile based on postal code), Charlson comorbidity index, comorbidities (hypertension, chronic kidney disease, pulmonary disease, cancer, infections, liver disease, obesity), number of outpatient visits, number of hospitalizations, number of emergency department visits, and medications (opioids, glucocorticoids, NSAIDs) were performed to assess the risk of 34 incident autoimmune diseases, as well as a composite outcome of all autoimmune diseases, all in separate analyses. All covariates were measured within the year prior to the index date. The Benjamini-Hochberg procedure was used to account for multiple testing. Results: We identified 257,224 SARS-CoV-2-positive patients and 771,352 SARS-CoV-2-negative patients. Mean follow-up time was 1.1 years for all autoimmune diseases. Baseline characteristics of participants are in Table 1. Compared with the SARS-CoV-2-negative patients, the SARS-CoV-2-positive patients had a statistically significant higher risk of developing rheumatoid arthritis (adjusted hazard ratios aHR (95% confidence interval CI: 1.20 (1.11-1.29)), type 1 diabetes mellitus (1.35 (1.15-1.60)), Graves' disease (1.21 (1.09-1.34)), alopecia areata (1.34 (1.13-1.58)), vitiligo (1.37 (1.00-1.91)), immune thrombocytopenic purpura (1.21 (1.05-1.38)), Guillain-Barre syndrome (1.74 (1.40-2.15)), pemphigus vulgaris (2.44 (1.11-5.33)), transverse myelitis (2.37 (1.42-3.97)), and the composite autoimmune disease outcome (1.11 (1.08-1.15)) (Figure 1). Conversely, SARS-CoV-2 patients had a statistically significant lower risk of polymyalgia rheumatica (aHR (95% CI): 0.79 (0.65-0.97)). After accounting for multiple testing, the above associations remained statistically significant except for polymyalgia rheumatica and pemphigus vulgaris. Conclusion: The risk of developing certain incident autoimmune diseases was increased following SARS-CoV-2 infection in our population-based study. These findings highlight the potential long-term consequences of SARS-CoV-2 infection. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared.