Long-term outcomes of patients with propylthiouracil-induced anti-neutrophil cytoplasmic auto-antibody-associated vasculitis

Abstract

Objective: It was well known that propylthiouracil (PTU) could induce ANCA-associated vasculitis (AAV) and clinical evident vasculitis could resolve after cessation of PTU with or without immunosuppressive therapy. However, the treatment strategy for patients with PTU-induced AAV remained inconclusive and their long-term outcomes were lacking. The aim of our study was to summarize these data.

Methods: Fifteen patients with PTU-induced AAV, receiving immunosuppressive agents for <12 months and following over 24 months, were selected in the current study. The clinical and pathological data, including treatment protocols and outcomes, were retrospectively investigated.

Results: All the patients were followed for a mean of 55.0 (25-98) months. PTU was discontinued upon diagnosis of PTU-induced AAV. Immunosuppressive therapy was administrated only for patients with vital organ involvements, such as lung and kidney, and lasted only 7.9 +/- 3.3 (0.27-12) months. No relapse of vasculitis occurred during follow-up, even after withdrawal of immunosuppressive therapy. Twelve (80%) patients remained in complete remission and one patient remained in partial remission at the latest follow-up. Two patients were treatment resistant due to late referral and late withdrawal of PTU, both of them progressed to end-stage renal disease. For uncontrolled hyperthyroidism on presentation, six patients switched to methimazole and none of them experienced relapse of vasculitis.

Conclusions: The long-term outcomes of patients with PTU-induced AAV were relatively good. PTU should be discontinued immediately after diagnosis. Immunosuppressive therapy may be only used in patients with vital organ involvements, and a long-term maintenance therapy may not be necessary.