OA05 Lower incidence of COVID-19 but higher mortality in patients with inflammatory arthritis compared to controls in Wales, United Kingdom: a population epidemiological study

Abstract Background/Aims To investigate whether inflammatory arthritis (rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS)) and/or their treatments predisposes patients with an increased risk of contracting COVID-19 and/or more severe infection. Methods A retrospective, population-based cohort study using linked, Welsh anonymised electronic health data from SAIL Databank, comprising primary care, secondary care, rheumatology clinic data, Office of National Statistics Mortality data and laboratory COVID-19-related datasets. Individuals aged 18 years or over who tested positive for COVID-19 in Wales for the period of analysis from 1st March 2020 to 12th May 2021 with READ Codes present for RA, PsA and AS in their primary care records formed the study population cases. The controls were individuals without IA codes present in their records. Results Over 3 million COVID-19 tests had been administered in Wales, UK during the study period. A total of 1966 IA patients and 166,602 controls had tested positive for COVID-19 and were included in analysis. The incidence rate was 3.5% (1966/56,914) for IA patients and 6% in controls (166,602/2,760,442) (Chi Square: p-value is < 0.00001). Individuals with IA were older and significantly more comorbid compared to controls. Significantly more patients with IA were hospitalised (difference: 13.9%; 95% CI: 12-15.8) or deceased (difference: 8%; 95% CI: 6.7-9.5) following COVID-19 infection compared to controls. In a cox proportional hazard model, adjusted for significant covariates, IA was not associated with higher risk of death following COVID infection (HR: 0.42, 95% CI: 0.14 to 1.29). Significant risk factors associated with increased risk of death included shielded status (HR: 1.38, 95% CI: 1.27 to 1.50), increasing age (HR: 1.08; 95% CI: 1.07-1.08), smoking (HR: 1.24; 95% CI: 1.15-1.35), diabetes (HR: 1.31; 95% CI: 1.22-1.41), hypertension (HR: 1.15; 95% CI: 1.07-1.23), cancer (HR: 1.07; 95% CI: 1.00-1.15) and previous serious infections (HR: 1.13; 95% CI: 1.06-1.21) were associated with increased risk of death in IA patients compared to controls. Hospitalisations 1-year prior to COVID-19 were associated with a more than threefold increased risk of death in IA patients compared to controls (HR: 3.15; 95% CI: 2.89-3.44). Conclusion Conclusion: IA patients had a lower risk of contracting COVID, probably as a result of shielding. IA was not directly associated with increased risk of death