COVID-19 in systemic vasculitis and polymyalgia rheumatica: who is at risk of poor outcomes?

The identification of populations at high risk of poor outcomes in COVID-19 is of utmost importance to prioritise preventive measures and, eventually, to guide early intervention to control the disease and its complications in selected groups.

Whether patients with rheumatic diseases have a worse prognosis in COVID-19 than the general population is still unclear;1, 2 however, cumulative evidence suggests that the association between systemic autoimmune disease and other factors, such as older age, a high burden of comorbidities, or high-dose glucocorticoid treatment is associated with admission to hospital and a poor prognosis.3, 4 Rheumatic diseases are highly heterogeneous, and the differential outcomes between people with different rheumatological conditions are likely to provide more informative data on the real risk in specific disease categories.

In The Lancet Rheumatology, Sebastian E Sattui and colleagues⁵ report novel results on the outcomes of COVID-19 in patients with primary systemic vasculitis or polymyalgia rheumatica. In their retrospective cohort study, the authors used data from the COVID-19 Global Rheumatology Alliance physician registry and the European Alliance of Associations for Rheumatology COVID-19 registry to provide the largest international cohort available to date, including 1202 cases of COVID-19 in patients with primary systemic vasculitis or polymyalgia rheumatica.

Research on the effects of SARS-CoV-2 infection in this group of patients is supported by intriguing speculations on the similarities between systemic vasculitis and COVID-19-related endothelial inflammation. Several manifestations resembling vasculitis have been described in COVID-19, including thromboembolism, multisystem inflammatory syndromes similar to Kawasaki disease, and vasculitis-like manifestations.⁶ Whether patients with primary systemic vasculitis might be more prone to the microvascular dysfunction caused by COVID-19 than patients with other rheumatological conditions or the general population is still to be elucidated. Moreover, some intrinsic risk factors for poor outcomes in COVID-19 can be hypothesised for each type of systemic vasculitis, including older age in giant cell arteritis and polymyalgia rheumatica, frequent severe pulmonary or renal comorbidities in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, and an increased risk of thrombotic manifestations in Behçet's syndrome. Furthermore, all of these conditions often require intensive immunosuppressive therapy regimens that might have a relevant effect on the severity of SARS-CoV-2 infection.

Indeed, the findings from the study by Sattui and colleagues⁵ show a high rate of severe COVID-19 outcomes in patients with primary systemic vasculitis or polymyalgia rheumatica, including 114 (11·2%) of 1020 patients hospitalised with no supplemental oxygen, 239 (23·4%) hospitalised with ventilation or supplemental oxygen and mortality in 155 (15·2%) patients. Although the poor outcomes might have been overestimated by selection or reporting bias in this physician-entered case-reporting registry, the study contributes to the identification of specific risk factors for poor prognosis in COVID-19 in this population of patients with rheumatic disease. Besides the well established poor prognostic factors, including older age (per each additional decade of life odds ratio [OR] 1·44 [95% CI 1·31–1·57]) and a higher number of comorbidities (per each additional comorbidity 1·39 [1·23–1·58]), Sattui and colleagues⁵ further identified disease-specific and treatment-specific risk factors that have important implications for the management of primary systemic vasculitis and polymyalgia rheumatica in the context of COVID-19. The type of diagnosis within primary systemic vasculitis was found to influence outcomes, which appeared to be worse in patients with giant cell arteritis and ANCA-associated vasculitis, and better in those with Behçet's syndrome. Furthermore, taking 10 mg/day or more of glucocorticoid (OR 2·14 [95% CI 1·50–3·04] in the whole cohort), rituximab (2·15 [1·15–4·01] for patients with ANCA-associated vasculitis), or cyclophosphamide (4·30 [1·10–16·75] for patients with ANCA-associated vasculitis) might also increase the risk of poor outcomes. Nonetheless, moderate, or high or severe disease activity was also identified as a risk factor (OR 2·12 [1·49–3·02] vs patients with disease remission or low disease activity), particularly in patients with ANCA-associated vasculitis, underlying the importance of avoiding disruption of care and the reduction or postponement of immunosuppressive treatment in patients with systemic vasculitis.

Reassuringly, outcomes improved during the period of observation in the study,⁵ implying a better management of COVID-19 and possibly the initial effect of the first patients receiving vaccination. The possible reduction in the effectiveness of COVID-19 vaccination due to vasculitis treatments, and especially rituximab, is another matter that should be taken into account, and requires continuous vigilance in these clinically vulnerable patients.⁷ Clarification of the optimal timing of vaccination in relation to some specific treatments in primary systemic vasculitis is warranted to improve protection of the patients at highest risk.⁸

In conclusion, Sattui and colleagues⁵ have helped to identify and characterise the most clinically vulnerable subgroup of patients with primary systemic vasculitis or polymyalgia rheumatica, and they have provided important and highly needed insights to guide the management of these patients during the COVID-19 pandemic. Additionally, this study emphasises the importance of multicentre, international efforts in the rheumatology community to gather valuable information on large cohorts of patients, even for rare forms of rheumatic disease.

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I declare no competing interests.