Therapy of rheumatoid arthritis with methotrexate. Claims data analysis of treatment patterns

Methotrexate (MTX) is the most important disease-modifying antirheumatic drug (DMARD) and is recommended by national and international guidelines as the first choice for treatment of rheumatoid arthritis (RA). Recent studies reporting prescription data of MTX captured only patients who were treated by rheumatologists. Therefore, the aim of the present study was to analyse several aspects of the prescription of MTX based on claims data. Outpatient and inpatient diagnoses as well as prescription data was available for 9579 RA patients for the years 2005-2008. Of the patients 45% were treated exclusively with parenteral MTX, 8% were treated exclusively with oral MTX and 48% switched between both forms of application. The average weekly dosage presribed in 70% of the patients was between 10 and 25 mg. The most common DMARD combination was MTX plus leflunomide with 16%. In 16% RA patients were treated with a combination of MTX and TNF-α inhibitors. Glucocorticoids were prescribed temporarily in 81% together with MTX and supplementation with folic acid was given only in 65%. The results of this study provide important insights into the drug supply of MTX to RA patients in the German statutory health care sector. In particular, the high frequency of prescriptions of parenteral MTX and the inadequate prescription of folic acid are different from the recently published multinational recommendations of the 3E initiative for the use of MTX.