What comes after the lockdown? Clustering of ANCA-associated vasculitis: single-centre observation of a spatiotemporal pattern.

Antineutrophil cytoplasm antibodies (ANCA)-associated vasculitides (AAV) are characterised by a heterogeneous clinical phenotype.1 We report a cluster of 15 patients diagnosed with AAV either de novo (n=11) or with relapsing disease (n=4) during COVID-19 pandemic between February and August 2020. During this period, we observed two major phenomena: (1) an incidence-shift with a ‘COVID-gap’ of no diagnosed AAV cases during the lockdown period (March and April), followed by a ‘postlockdown cluster’ of 14 active patients (8 myeloperoxidase-ANCA, 6 proteinase 3-ANCA vasculitis) in the subsequent 4 months and (2) an increased incidence rate (figure 1 and online supplemental figure S3). Mean creatinine at baseline was 3.66 mg/dL. Inflammatory markers were significantly elevated in most patients, with a mean C reactive protein value of 9.93 mg/dL and an erythrocyte sedimentation rate of 83 mm per first hour. Despite detrimental effects on humoral immunity,2 most patients received two doses of rituximab and methylprednisolone. No severe treatment complications occurred. SARS-CoV-2 PCR and serology were negative in tested patients. Further clinical and radiological characteristics are provided in online supplemental tables S1 and S2).### Supplementary data [annrheumdis-2020-219212supp001.pdf] ### Supplementary data [annrheumdis-2020-219212supp002.pdf] ### Supplementary data [annrheumdis-2020-219212supp003.pdf] ### Supplementary data [annrheumdis-2020-219212supp004.pdf] Figure 1 Timeline of incident ANCA-associates vasculitis cases in 2018, 2019 and 2020. Incident cases are posed on a timeline at …