Clinical Summary

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What was studied

A retrospective nationwide cohort from Korea (K-COV-N) compared people with confirmed COVID-19 (October 8, 2020–December 31, 2022) to controls from 2018 health examinations to assess long-term (>180 days) risk of autoimmune and autoinflammatory connective tissue disorders using inverse probability weighting.

Key findings

Among 6,912,427 participants (3,145,388 COVID-19; 3,767,039 controls), COVID-19 was associated with higher adjusted hazard for several outcomes: alopecia areata 1.11 (95% CI, 1.07-1.15), alopecia totalis 1.24 (1.09-1.42), vitiligo 1.11 (1.04-1.19), Behcet disease 1.45 (1.20-1.74), Crohn disease 1.35 (1.14-1.60), ulcerative colitis 1.15 (1.04-1.28), rheumatoid arthritis 1.09 (1.06-1.12), systemic lupus erythematosus 1.14 (1.01-1.28), Sjogren syndrome 1.13 (1.03-1.25), ankylosing spondylitis 1.11 (1.02-1.20), and bullous pemphigoid 1.62 (1.07-2.45); risks were higher with ICU-level severity, during the Delta period, and without vaccination (no effect sizes provided).

Clinical implications

Monitor for autoimmune and autoinflammatory connective tissue disorders after COVID-19, with extra vigilance after severe infection, during Delta-period infections, and in unvaccinated patients. Consider sex and age when assessing risk, as associations varied across these groups.