A pioneering new study from researchers at Reims University Hospital in France has unveiled a promising way to accurately measure whether rheumatoid arthritis (RA) patients are adhering to their prescribed methotrexate medication regimen. The study, published in the journal Rheumatology, utilized a urinary methotrexate (MTX) dosage test to directly measure adherence levels.
Medication non-adherence is a major barrier to effective treatment for many chronic conditions like RA. However, existing techniques to estimate adherence, such as patient self-reports and pharmacy refill rates, are indirect and imprecise. The new urinary MTX test gets around this limitation by directly measuring the levels of the drug present in a patient’s system.
The cross-sectional study included 84 RA patients who had been receiving methotrexate for at least 6 months. In addition to providing urine samples for MTX level testing, participants completed questionnaires about adherence, symptoms, and side effects. The urinary MTX test showed that 91.7% of patients were adhering to their methotrexate doses, much higher than adherence rates estimated by self-reported questionnaires (61.9%) or pharmacy refill data (69.5%). Patients flagged as non-adherent by the urine test had more tender joints and elevated inflammatory markers.
The study is the largest yet evaluating real-world adherence to methotrexate treatment in rheumatoid arthritis using an objective urinary biomarker. The results underscore how indirect adherence measurements can grossly underestimate adherence levels. The urinary methotrexate test gives an accurate adherence picture.
The researchers suggest the urine test could be utilized for RA patients experiencing an unexplained lack of treatment response or frequent flare-ups before considering more aggressive therapy escalations. Identifying non-adherence through the objective test could avoid unnecessary treatment changes. With this validated biomarker, patients struggling with adherence issues can be pinpointed and provided with the support they need. It is a powerful new tool to optimize rheumatoid arthritis care on an individual level.
Reference
Théate N, Geoffroy M, Kanagaratnam L, Gozalo C, Charlot I, Bolko L, et al. Urinary methotrexate dosage in rheumatoid arthritis, in patients treated for at least 6 months: a potential marker of adherence. RMD Open. 2024 May 1;10(2):e004024.