Avacopan was linked to fewer severe infections in ANCA-associated vasculitis, in a small observational cohort

Design

Multicentre retrospective cohort with time-varying exposure and inverse probability weighting

Population

387 patients with ANCA-associated vasculitis (52 given avacopan, 335 not)

Primary outcome

Recurrent relapse and severe infection requiring hospitalisation

Effect

Severe infection adjusted HR 0.22 (95% CI 0.07 to 0.68); relapse not significantly different

This multicentre retrospective cohort study included 387 patients with ANCA-associated vasculitis, 52 of whom received avacopan. It modelled avacopan as a time-varying exposure and weighted for baseline differences. Severe infection meant infection needing hospital admission.

Avacopan exposure was associated with a lower risk of severe infection (adjusted HR 0.22, 95% CI 0.07 to 0.68), and with lower prednisolone exposure over time. There was no significant difference in relapse. The infection association stayed in the same direction when glucocorticoid exposure was modelled, but its size varied with the model.

With only 52 treated patients and a wide interval, the estimate is imprecise. The authors note that the observational design precludes a causal conclusion.

• Consider the steroid-sparing effect of avacopan when infection risk is a concern.
• Do not expect fewer relapses; none was shown here.
• Check local availability and funding before planning treatment.
• Treat the hazard ratio as hypothesis-generating, given 52 treated patients.
• Continue to minimise glucocorticoid exposure by other means.

Why it matters

Infection and steroid toxicity are two of the main harms of treating ANCA vasculitis.

Don't overread it

Retrospective, with 52 treated patients; it does not show that avacopan causes fewer infections or that it should replace standard regimens.

The statistics, in plain English

A hazard ratio of 0.22 means about four-fifths lower rate of severe infection, but the interval runs from 0.07 to 0.68, so the true effect could be much smaller or larger. Weighting balances measured differences, not unmeasured ones such as who was chosen for avacopan.

Read the rest in the app

You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.

Get Daily Doctor — free

Scan to keep reading on your phone. No account needed to start.