Methotrexate (MTX) is used at low doses to treat rheumatologic disorders in the paediatric age group. Toxicity is observed despite the low doses used. Even though recommendations for monitoring of early signs of toxicity exist in many countries, real-life practice may vary. We therefore assessed current practice in Germany, Switzerland and Austria.
A 22-item questionnaire regarding practices of monitoring MTX therapy was sent by email to all members of the Society for Paediatric and Adolescent Rheumatology (GKJR, n=224). Responses were compared to evidence-based recommendations.
72 of 209 physicians with valid e-mail addresses returned a completed questionnaire (response rate, 34%). Of these, 8 (11%), 18 (25%), 25 (34%) and 21 (29%) reported that they had been treating paediatric patients with rheumatologic disorders for <5 years, 5-10 years, 10-20 years, and >20 years, respectively. Of the tests recommended for routine monitoring, haemogram and liver transaminases were used by all respondents, followed by serum creatinine (97%) and urinalysis (88%). Of the tests not recommended for this purpose, abdominal ultrasound (including liver and kidney), echocardiography, and pulmonary function tests were reported by 51%, 36%, and 51%, respectively, and all three modalities by 28%. The latter was positively associated with a longer duration of practicing paediatric rheumatology but not with the number of patients seen annually.
Real-life practice of MTX toxicity monitoring in the studied population deviated from evidence-based recommendations in the direction of overusing equipment-based testing, which apparently was more pronounced among more senior practitioners.