Clinical and histological features of antineutrophil cytoplasmic antibody-associated vasculitis related to antithyroid drugs .

BACKGROUND

Antithyroid drugs such as propylthiouracil and methimazole have been reported to cause antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), but little is known about long-term outcomes.

MATERIALS AND METHODS

We identified AAV patients who underwent renal biopsy and retrospectively assessed their clinical and histological findings. Patients with AAV who had received propylthiouracil or methimazole were defined as having antithyroid drug-associated AAV (ATD-AAV), and the other patients were defined as having primary AAV.

RESULTS

Seven patients with ATD-AAV and 83 patients with primary AAV were identified. Compared with the primary AAV group, the patients with ATD-AAV were significantly younger (mean ± standard deviation; 45.4 ± 21.4 years vs. 65.9 ± 13.8 years, p < 0.01), and had lower serum creatinine (median [interquartile range]; 0.7 mg/dL [0.6 - 1.5] vs. 2.3 mg/dL [1.0 - 4.0], p = 0.02), as well as a higher frequency of positivity for MPO--ANCA/PR3-ANCA (42.9 vs. 4.8%, p < 0.01). While glomerular crescents varied, interstitial fibrosis and tubular atrophy were milder in ATD-AAV patients. Kaplan-Meier analysis showed a significantly higher kidney survival rate in patients with ATD-AAV than in those with primary AAV (p = 0.05).

CONCLUSION: Patients with ATD-AAV were younger and had milder kidney involvement, resulting in a better long-term outcome compared with primary AAV.
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