Higher risk of Long COVID among patients with autoimmune rheumatic diseases and immunomodulatory therapy: a retrospective cohort analysis of national US data.

BACKGROUND: Little is known about the prevalence of and factors associated with Long COVID in patients with autoimmune rheumatic diseases (AIRDs). METHODS: We conducted a retrospective cohort study using data from the National Clinical Cohort Collaborative (N3C). We included adults with a first documented SARS-CoV-2 infection between September 2021 and December 2023, with follow-up through December 2024. Long COVID was defined as ICD-10-CM code U09.9 or a Long COVID clinic visit occurring 28 to 365 days after first infection. We compared patients with AIRD with matched non-AIRD controls using 1:1 nearest-neighbor propensity score matching on age with exact matching on sex, race/ethnicity, SARS-CoV-2 variant-dominant period, and data-contributing organization. We estimated hazard ratios using multivariable Cox regression models. Among people with AIRD, we assessed risk by AIRD type and medication exposure before acute COVID-19. RESULTS: In the matched cohort of 187,106 patients, Long COVID occurred in 2.8% of AIRD patients and 1.5% among non-AIRD patients. In multivariable analyses, AIRD was associated with an increased risk of Long COVID compared with non-AIRD patients (aHR 1.56, 95% CI 1.45-1.67). Among patients with AIRD, higher acute COVID-19 severity, pulmonary disease, obesity, and exposure to rituximab or glucocorticoids were associated with an increased risk of Long COVID. Sjögren's syndrome was associated with a higher risk of Long COVID. CONCLUSION: The higher risk of developing Long COVID among AIRD patients compared with those without AIRD underscores the need to identify potential risk factors for Long COVID in this population to minimize its long-term effects.