COVID-19 admissions and mortality in patients with early inflammatory arthritis: results from a UK national cohort

Objective To describe the risks and predictors of coronavirus disease 2019 (COVID-19) hospitalization and mortality among patients with early inflammatory arthritis (EIA), recruited to the National Early Inflammatory Arthritis Audit (NEIAA). Methods NEIAA is an observational cohort. We included adults with EIA from Feb 2020 to May 2021. Outcomes of interest were hospitalization and death due to COVID-19, using NHS Digital linkage. Cox proportional hazards were used to calculate hazard ratios for outcomes according to initial treatment strategy, with adjustment for confounders. Results From 14 127 patients with EIA, there were 143 hospitalizations and 47 deaths due to COVID-19, with incidence rates per 100 person-years of 0.93 (95% CI 0.79, 1.10) for hospitalization and 0.30 (95% CI 0.23, 0.40) for death. Increasing age, male gender, comorbidities and ex-smoking were associated with increased risk of worse COVID-19 outcomes. Higher baseline DAS28 was not associated with COVID-19 admissions [confounder adjusted hazard ratio (aHR) 1.10; 95% CI 0.97, 1.24] or mortality (aHR 1.11; 95% CI 0.90, 1.37). Seropositivity was not associated with either outcome. Higher symptom burden on patient-reported measures predicted worse COVID-19 outcomes. In unadjusted models, CS associated with COVID-19 death (HR 2.29; 95% CI 1.02, 5.13), and SSZ monotherapy associated with COVID-19 admission (HR 1.92; 95% CI 1.04, 3.56). In adjusted models, associations for CS and SSZ were not statistically significant. Conclusion Patient characteristics have stronger associations with COVID-19 than the initial treatment strategy in patients with EIA. An important limitation is that we have not looked at treatment changes over time.