Longterm observational study of methotrexate use in a Dutch cohort of 1022 patients with rheumatoid arthritis

OBJECTIVE: To study which factors are associated with longterm methotrexate (MTX) use in rheumatoid arthritis (RA). METHODS: All patients with RA who had started MTX after January 1, 1993, were selected from a regional hospital based registration system. Data on demographic and clinical features were retrieved through chart review. By means of life table analysis and Cox regression analysis, MTX survival and the relation between demographic variables, clinical features, and MTX survival were studied. RESULTS: A total of 1072 MTX treatment episodes in 1022 patients were analyzed. The cumulative MTX survival probability after 5 years was 64%, and after 9 years was 50%. Univariate analysis showed a significant relation between MTX survival probability and folic acid supplementation, attending rheumatologist, concurrent prednisolone use, concurrent sulfasalazine use, and the number of previous disease modifying drugs. In the multivariate analysis folic acid supplementation, attending rheumatologist, and concurrent prednisolone use remained significantly related to MTX survival. Age, disease duration, and creatinine clearance were not. CONCLUSION: In this retrospective study of 1022 patients with RA the cumulative MTX survival probability was 64% after 5 years and 50% after 9 years. Folic acid supplementation and to a lesser extent prednisolone were associated with a longer MTX survival. In addition, treatment strategies of individual rheumatologists influenced MTX survival.