The aims of this study were to describe the rate of leflunomide discontinuation in rheumatoid arthritis (RA) patients, in standard clinical practice, and to analyse which factors could influence this rate, paying particular attention to the concomitant treatment with other disease-modifying anti-rheumatic drugs (DMARDs).
We selected RA patients, diagnosed according to the 1987 American College of Rheumatology (ACR) criteria, attending the rheumatology outpatient clinic of the San Carlos Clinical Hospital (Madrid, Spain), who had started treatment with leflunomide between 1 January 2006 and 1 January 2011. Clinical records were examined until withdrawal of the drug, loss of follow-up, or 1 October 2011. Kaplan-Meier curves were set to account for leflunomide withdrawal. Cox bivariate and multivariate regression models were conducted to examine risk factors for leflunomide discontinuation.
The incident rate (IR) for leflunomide discontinuation, regardless of the cause, was 27 per 100 patient-years [95% confidence interval (CI) 22-31]. We observed, in both the bivariate and multivariate regression analysis, that those aged > 75 years at the start of the leflunomide treatment and undergoing concurrent treatment with methotrexate (MTX) and/or hydroxychloroquine (HC) had a significantly higher risk of leflunomide discontinuation.
An older age at the start of the treatment with leflunomide, or concomitant treatment with MTX and/or HC, could be associated with a higher risk of leflunomide discontinuation, regardless of the cause. Therefore, when taking MTX or HC, patients receiving leflunomide should be closely monitored early to detect the occurrence of adverse reactions, and hence prevent their aggravation.