Clinical characteristics of myeloperoxidase antineutrophil cytoplasmic antibody-associated vasculitis caused by antithyroid drugs.

Context: The clinical characteristics of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis caused by antithyroid drugs are still unclear because most reports describe only a small number of patients. Objective: The objective was to analyze a large number of patients with MPO-ANCA-associated vasculitis to determine the time of onset, the drug and dose taken, the clinical symptoms, the relationship between the clinical symptoms and the MPO-ANCA titer, and the incidence. Design: We analyzed 92 patients in whom the adverse reaction of MPO-ANCA-associated vasculitis was reported to Chugai Pharmaceutical, a company that markets antithyroid drugs. Results: Of the 92 patients, 41 (44.6%) had single-organ failure, 32 (34.8%) had two-organ failure, 13 (14.1%), had three-organ failure, and two (2.2%) had four-organ failure. The number of organs involved was unknown in the other four patients (4.3%). The median time of onset was 42 months (range, 1–372 months) after starting drug tr...