Severe COVID-19 outcomes among patients with autoimmune rheumatic diseases or transplantation: a population-based matched cohort study

OBJECTIVES: To assess the risk of severe COVID-19 outcomes in patients with autoimmune rheumatic diseases (ARDs) and transplant recipients compared with matched general population comparators. DESIGN: Population-based matched cohort study using administrative health data sets. SETTING: British Columbia, Canada. PARTICIPANTS: All adults with test-positive SARS-CoV-2 infections. SARS-CoV-2-positive patients with ARDs and those with transplantation were matched to SARS-CoV-2-positive general population comparators on age (±5 years), sex, month/year of initial positive SARS-CoV-2 test and health authority. OUTCOME MEASURES: COVID-19-related hospitalisations, intensive care unit (ICU) admissions, invasive ventilation and COVID-19-specific mortality. We performed multivariable conditional logistic regression models adjusting for socioeconomic status, Charlson Comorbidity Index, hypertension, rural address and number of previous COVID-19 PCR tests. RESULTS: Among 6279 patients with ARDs and 222 transplant recipients, all SARS-CoV-2 test positive, risk of hospitalisation was significantly increased among patients with ARDs (overall ARDs (adjusted OR (aOR) 1.30; 95% CI 1.19 to 1.43)); highest within ARDs: adult systemic vasculitides (aOR 2.18; 95% CI 1.17 to 4.05) and transplantation (aOR 10.56; 95% CI 6.88 to 16.22). Odds of ICU admission were significantly increased among patients with ARDs (overall ARDs (aOR 1.30; 95% CI 1.11 to 1.51)); highest within ARDs: ankylosing spondylitis (aOR 2.03; 95% CI 1.18 to 3.50) and transplantation (aOR 8.13; 95% CI 4.76 to 13.91). Odds of invasive ventilation were significantly increased among patients with ARDs (overall ARDs (aOR 1.60; 95% CI 1.27 to 2.01)); highest within ARDs: ankylosing spondylitis (aOR 2.63; 95% CI 1.14 to 6.06) and transplantation (aOR 8.64; 95% CI 3.81 to 19.61). Risk of COVID-19-specific mortality was increased among patients with ARDs (overall ARDs (aOR 1.24; 95% CI 1.05 to 1.47)); highest within ARDs: ankylosing spondylitis (aOR 2.15; 95% CI 1.02 to 4.55) and transplantation (aOR 5.48; 95% CI 2.82 to 10.63). CONCLUSIONS: The risk of severe COVID-19 outcomes is increased in certain patient groups with ARDs or transplantation, although the magnitude differs across individual diseases. Strategies to mitigate risk, such as booster vaccination, prompt diagnosis and early intervention with available therapies, should be prioritised in these groups according to risk.