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Adherence to low-dose methotrexate in children with juvenile idiopathic arthritis using a sensitive methotrexate

Julia E Möhlmann1, Sytze de Roock2, Annelies C Egas3

  • 1Department of Clinical Pharmacy, University Medical Centre Utrecht, Utrecht University, Utrecht, The Netherlands. j.e.mohlmann@umcutrecht.nl.

Pediatric Rheumatology Online Journal
|May 7, 2024
PubMed
Abstract

Insights

Assessing methotrexate (MTX) adherence in juvenile idiopathic arthritis patients using plasma drug levels revealed lower adherence over time, particularly in teenagers. This objective method can help clinicians evaluate patient adherence.

Area of Science:

  • Pediatric Rheumatology
  • Pharmacokinetics
  • Drug Adherence

Background:

  • Low-dose weekly methotrexate (MTX) is a primary treatment for juvenile idiopathic arthritis (JIA).
  • Insufficient treatment efficacy in a significant portion of JIA patients may stem from suboptimal drug adherence.
  • Objective assessment of MTX adherence is crucial for optimizing JIA management.

Purpose of the Study:

  • To evaluate methotrexate (MTX) adherence in juvenile idiopathic arthritis (JIA) patients by measuring plasma MTX concentrations.
  • To investigate the relationship between plasma MTX levels and self-reported adherence issues or concurrent biologic use.

Main Methods:

  • Retrospective observational study involving plasma samples from JIA patients.
  • Development of an ultrasensitive liquid chromatography-tandem mass spectrometry method for MTX and 7-hydroxy-MTX quantification.
  • Comparison of determined plasma MTX concentrations against adherence thresholds to categorize patients as adherent or possibly non-adherent.

Main Results:

  • Adherence to MTX was 88% shortly after treatment initiation, decreasing to 77% after one year in 43 analyzed JIA patients.
  • Teenagers demonstrated a significantly higher risk of non-adherence (p=0.002).
  • No significant association was found between MTX adherence and self-reported adherence issues (p=1.00) or concomitant biologic use (p=0.27).

Conclusions:

  • Plasma MTX quantification offers a feasible and objective method for assessing adherence in low-dose weekly MTX therapy for JIA.
  • This method can assist clinicians in confirming or refuting suspected non-adherence.
  • Adherence declines over time, highlighting the need for ongoing monitoring in JIA patients.
Keywords:
Adherence assayDrug adherenceJIAJuvenile idiopathic arthritisMTXMethotrexate

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