Leflunomide Does Not Cause Interstitial Lung Disease
Reports of link likely result from channeling of high-risk patients to the drug
MONDAY, May 15 (HealthDay News) -- Reports that the disease-modifying antirheumatic drug (DMARD) leflunomide causes interstitial lung disease (ILD) in rheumatoid arthritis patients appear to be unfounded, according to a study in the May issue of Arthritis & Rheumatism.
Samy Suissa, Ph.D., of McGill University Health Centre in Montreal, Quebec, and colleagues conducted a population-based epidemiologic study by using the PharMetrics claims database to identify 62,734 rheumatoid arthritis patients who had received a DMARD between September 1998 and the end of 2003. Each of the 74 cases of ILD serious enough to require hospitalization was matched to 100 controls.
The rate of serious ILD was 8.1 per 10,000 patients per year. A nearly twofold risk of ILD was observed with leflunomide use. However, no excess risk was observed in subjects with no history of ILD and no previous use of methotrexate, a DMARD associated with pulmonary toxicity. Patients with a history of ILD were twice as likely to have been given leflunomide rather than another DMARD.
"The increased risk of ILD in the patients treated with leflunomide appears to be due to a channeling bias, where patients with a history of ILD may have been preferentially prescribed leflunomide rather than methotrexate on the assumption that, in contrast to methotrexate, no lung toxicity was associated with leflunomide," the authors conclude.
The study was supported by a grant from Sanofi-Aventis.