A team of international researchers have identified the key risk factors associated with poor outcomes from COVID-19 in patients with primary systemic vasculitis or polymyalgia rheumatica.

The analysis found patients with giant cell arteritis and ANCA-associated vasculitis have particularly high rates of severe COVID-19 outcomes, and the findings could help clinicians advise on risk mitigation strategies for their patients, they concluded.

Data on just over 1,000 adult patients with the conditions in the COVID-19 Global Rheumatology Alliance physician registry and EULAR COVID-19 registry showed that 23.4% were hospitalised and needed oxygen therapy or ventilation. Another 11.2% were hospitalised but without the need for oxygen.

Reporting in The Lancet Rheumatology, the research team, which included several UK rheumatologists,  said 15.2% of the cohort died.

There was a higher chance of poor COVID-19 outcomes in patients who were older (increasing by 44% with each decade), were male compared with female (38% increased odds) had more comorbidities (39% increased risk with each co-morbidity) and were taking 10 mg/day or more of prednisolone compared with none (more than double the risk).

Increased odds of severe COVID-19 outcomes were also found with those who had moderate, or high or severe disease activity compared with those who had disease remission or low disease activity (also more than double the risk).

But risk factors varied among different disease subtypes. Among patients with ANCA-associated vasculitis, almost two-thirds were hospitalised and a fifth died and a high proportion of patients with giant cell arteritis also had poor outcomes, they reported.

By comparison, in polymyalgia rheumatica, poor outcomes were only associated with age as has been seen as a risk factor in the general population.

The researchers did report that those who had COVID-19 later in the analysis period (October 2020 to April 2021) had lower rates of poor outcomes which could relate to better management of COVID-19 as therapies were proven to be beneficial.

Important predictors of poor outcomes identified by the study included the use of high-dose glucocorticoids as well as receiving rituximab or cyclophosphamide, they said. The study could not say whether that reflected the immunosuppressive effects of the drugs or something about the type of patients prescribed them.

In those patients with many risk factors, paying attention to the ones that can be modified, such as prescription of high-dose glucocorticoids is crucial, they added.

“Different risk factors, including particular treatments and increased disease activity, were associated with poor COVID-19 outcomes in patients with primary systemic vasculitis or polymyalgia rheumatica. 

“The identified risk factors could help to guide physicians in recommending mitigation strategies for their patients,” the authors concluded.