Clinical

Folate supplement improves response to methotrexate in rheumatoid arthritis

Last Updated: 2003-05-12 14:37:13 -0400 (Reuters Health)

NEW YORK (Reuters Health) - A variety of factors, including folate supplementation, influence toxicity, efficacy and other aspects of methotrexate therapy in patients with rheumatoid arthritis, Dutch researchers report in the May issue of the Annals of the Rheumatic Diseases.

Dr. M. Hoekstra of Medisch Spectrum Twente, Enschede, and colleague note that although methotrexate is an effective disease-modifying drug in such patients, factors influencing toxicity, efficacy and final dosage are not well defined.

To explore factors relevant to daily clinical practice, the researchers studied data from a 48-week clinical trial of methotrexate therapy, starting at 7.5 mg/week, in rheumatoid arthritis patients. The subjects had been randomized to receive folate or placebo supplementation.

Analysis showed that folate supplementation was "strongly" related to a lack of hepatotoxicity. A high body mass index (BMI) was related to its occurrence. Prior gastrointestinal (GI) events and being younger were associated with diarrhea.

The main reasons for withdrawal from treatment were hepatotoxicity and adverse GI events. These were associated with lack of folate supplementation, BMI, prior GI events and being female.

Treatment efficacy was associated with low disease activity at baseline, being male, use of non-steroidal anti-inflammatory drugs and lower creatinine clearance.

Overall, the researchers suggests that in light of these findings, patients without prior GI events or a high BMI, who have a calculated creatinine clearance of 50 mL/min or more, "can start with 15 mg/week methotrexate provided that folates are added to the treatment."

Ann Rheum Dis 2003;62:423-426.