METHODS: This was a retrospective, observational study using plasma samples from juvenile idiopathic arthritis patients. An ultrasensitive liquid chromatography-tandem mass spectrometry method was developed for quantification of MTX and its metabolite 7-hydroxy-MTX in plasma. The determined MTX plasma concentrations in juvenile idiopathic arthritis patients were compared with corresponding adherence limits, categorising them as either adherent or possibly non-adherent to MTX therapy.
RESULTS: Plasma samples of 43 patients with juvenile idiopathic arthritis were analysed. Adherence to MTX in this population was 88% shortly after initiation of MTX therapy and decreased to 77% after one year of treatment. Teenagers were more at risk for non-adherence (p = 0.002). We could not find an association between MTX adherence with either self-reported adherence issues, nor with the use of concomitant biological treatment (p = 1.00 and p = 0.27, respectively; Fisher\'s Exact).
CONCLUSIONS: Quantification of MTX in plasma is a feasible and objective method to assess adherence in patients using low-dose weekly MTX. In clinical practice, the use of this method could be a helpful tool for physicians to refute or support suspicion of non-adherence to MTX therapy.
方法:这是一个回顾性研究,使用幼年特发性关节炎患者血浆样本的观察性研究。建立了一种超灵敏的液相色谱-串联质谱法,用于定量血浆中MTX及其代谢物7-羟基-MTX。将测定的青少年特发性关节炎患者的MTX血浆浓度与相应的依从性限值进行比较,将它们归类为粘附或可能不粘附MTX治疗。
结果:分析了43例幼年特发性关节炎患者的血浆样本。MTX治疗开始后不久,该人群对MTX的依从性为88%,治疗一年后下降至77%。青少年更容易出现不依从(p=0.002)。我们找不到MTX依从性与任何自我报告的依从性问题之间的关联,也不使用伴随的生物治疗(分别为p=1.00和p=0.27;Fisher精确)。
结论:血浆中MTX的定量是评估每周低剂量MTX患者依从性的可行且客观的方法。在临床实践中,这种方法的使用可能是医师反驳或支持不坚持MTX治疗的有用工具.