[Therapeutic maintenance level of methotrexate in rheumatoid arthritis]

To determine the probability of drug continuation, the reasons for discontinuation of methotrexate (MTX), and risk factors of treatment termination in rheumatoid arthritis.

Retrospective cohort study of a 100 case follow-up between 1983 and 2003, all treated with MTX. Factors associated with toxicity, and efficacy of MTX were studied. Logistic regression was used to study the relation between baseline variables and various dependent factors.

Eighty three women and seventeen men were included in this study. The mean age at commencement of MTX was 45+/-13.7 (18-81) years. The mean duration of disease was 9.5+/-8.7 (0.25-40) years. The mean weekly dose of MTX was 9.8+/-3.4 mg/week. The therapeutic maintenance level of MTX was 76% at one year, 63% at 2 years and 45% at 5 years. The median of treatment duration was 10 (0. 5-40) months. Reasons for patients stopping MTX were: Adverse effects (15), lack of effect (1), non medical reasons (14) essentially because of financial difficulties. Baseline white blood cell counts >9 giga/mm3 (RR: 3.17) [95 %:1.03-9.74] (p=0.04) and baseline serum creatinine level >72 micromol/L (RR: 8.6) [95 %:1.04-71.17] (p=0.04) were associated with an increased risk of treatment termination.

The continuation rate of methotrexate in our study was good, despite the poor compliance with the treatment due to financial difficulties.