Risk factors of severe infections in patients with rheumatoid arthritis treated with leflunomide

Objectives: To determine the risk of severe infection requiring or complicating hospitalization associated with leflunomide therapy in patients with rheumatoid arthritis (RA). Methods: We performed a retrospective study of RA patients who were prescribed leflunomide between 2004 and 2011. Background clinical and laboratory features were compared between patients who suffered severe leflunomide-associated infections and those who did not. Results: Since January 2005, 401 RA patients have started on leflunomide. Among those, 33 (8.2 %) developed severe infections: pneumonia, oral candidiasis, pyelonephritis, pulmonary tuberculosis, cellulitis, disseminated herpes zoster, tonsillitis, and pulmonary cryptococcosis. Logistic regression showed that age at entry, the presence of DM, and daily dosage of corticosteroid were associated with development of severe infections. Conclusions: These results showed that some patients with RA who were taking leflunomide developed severe infections requiring hospitalization, and that older age, DM, and a higher daily dosage of corticosteroid were risk factors associated with leflunomide-associated severe infections.