O06 Baseline predictors of methotrexate-related adverse events in methotrexate-naïve patients with RA

Abstract

Abstract Background/Aims Methotrexate (MTX) is the most common treatment for rheumatoid arthritis (RA). The prevalence of adverse events (AEs) associated with MTX treatment for RA have been studied extensively, but there are limited data on the predictors of these AEs. This study aims to summarise the prevalence rates of MTX AEs, including gastrointestinal (GI), neurological, mucocutaneous, and elevated alanine transaminase (ALT) enzyme, and to identify baseline demographic and clinical predictors of these AEs. Methods The Rheumatoid Arthritis Medication Study (RAMS) is a UK multi-centre prospective cohort study of patients with RA starting MTX for the first time. Relevant demographic, medication, clinical and disease related data were collected at baseline. AEs were reported at six and twelve months follow-ups. The prevalence rates of AEs were calculated based on the proportions of patients who reported having had an AE within one year of follow-up. The associations between candidate baseline predictors and AEs were assessed using multivariable logistic regression. Results A total of 2,089 patients were included with a mean age of 58.4 (standard deviation: 13.5) years, 1390 (66.5%) were women. 1,814 and 1,579 patients completed the 6 and 12 months follow-up visits, respectively. The prevalence rates of the AEs within one year of follow-up were: GI = 777 (40.6%), mucocutaneous = 441 (23.1%), neurological = 487 (25.5%), elevated ALT (> upper limit of normal [ULN]) = 286 (15.5%). Younger age and being a woman were associated with increased risk of GI AEs, (age: OR 0.97 per year increase in age, 95% CI 0.98, 1.00; male sex: OR 0.58 vs female, 95% CI 0.46, 0.74) (Table 1). Higher baseline Health Assessment Questionnaire (HAQ) score was an independent predictor of GI, mucocutaneous, and neurological AEs. Furthermore, having ALT >1xULN at baseline or history of diabetes was associated with increased risk of subsequent ALT elevation during the study follow-up. Conclusion In patients with RA starting MTX, GI AEs were the most commonly reported AEs during the first year of follow-up. The identified predictors of AEs may facilitate discussions between clinicians and patients prior to commencing MTX, and may lead to increased adherence and consequently improved effectiveness. Disclosure A.A. Sherbini: None. J.M. Gwinnutt: Grants/research support; BMS. K.L. Hyrich: Member of speakers’ bureau; Abbvie. Grants/research support; Pfizer, UCB, BMS. S.M.M. Verstappen: Consultancies; Celltrion. Member of speakers’ bureau; Pfizer. Grants/research support; BMS.