Risk of autoimmune diseases in patients with Covid-19

ABSTRACT

Background: There are a number of emerging case reports of various autoimmune diseases occurring after Covid-19, yet there is still no large-scale population-based evidence to support this potential association. This study provides a closer insight into the association between Covid-19 and autoimmune diseases and reveals discrepancies across sex, age and race of participants. Method(s) This is a retrospective cohort study based on the TriNetX US Collaborative Network. In the test-negative design, cases (N = 1,118,682) were participants with positive polymerase chain reaction (PCR) test results for severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2), while controls were participants who tested negative and were not diagnosed Covid-19 throughout the follow-up period. The primary end points are incidence of newly-recorded autoimmune diseases. Hazard ratios (HRs) and 95% CIs of autoimmune diseases were calculated between propensity score-matched groups. We set osteoporosis as a negative control outcome to examine possible unmeasured confounders. We used another TriNetX database called Global Network for cross-validation to mitigate regional bias. Result(s) After propensity score matched for age, sex, race, socioeconomic status, and lifestyles variables, Covid-19 group exhibited significant higher risk of rheumatoid arthritis (HR1.190, 95% CI1.144-1.237), polymyalgia rheumatic (HR1.147, 95% CI1.016-1.296), vasculitis (HR1.524, 95% CI1.407-1.651), psoriasis (HR1.264, 95% CI1.203-1.329), and type 1 diabetes (HR1.144, 95%CI1.100-1.190), whereas it was associated with lower risk of systemic sclerosis (HR0.767, 95% CI0.668-0.881) and inflammatory bowel disease (HR0.914, 95% CI0.890-0.939). In general, age, sex, race and sensitivity analysis showed consistent trends in all strata. Conclusion(s) Covid-19 appears to be associated with a different degree of risk for various autoimmune diseases. Our preliminary findings have implications for clinical services and further research for mechanism is mandatory.