POS1489-HPR DRUG-RELATED PROBLEMS EXPERIENCED BY PATIENTS WITH RHEUMATOID ARTHRITIS AFTER METHOTREXATE TREATMENT INITIATION: AN OBSERVATIONAL STUDY
Authors: M. Oude Lansink, S. Pongers, C. Bekker, D. Ten Cate, B. Van den Bemt, V. Huiskes
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> According to the EULAR, methotrexate (MTX) is the cornerstone of rheumatoid arthritis (RA) treatment due to a favourable cost-effectiveness and safety profile. However, almost half of the patients are non-adherent to MTX and 25% discontinue MTX after one year [1]. Improving MTX drug adherence and persistence might result in better treatment outcomes for patients and reduced drug costs (as fewer and less expensive treatments would be required). Drug-related problems (DRP) can negatively affect drug persistence, adherence, cost-effectiveness and a patient's well-being. Because DRPs mostly arise during therapy initiation, insight into the frequency and type of DRPs that patients experience in the first three months of MTX use is needed to objectify the problem and find targets to improve MTX treatment outcomes. <h3>Objectives:</h3> To identify the number and type of DRPs experienced by patients with RA upon MTX treatment initiation. <h3>Methods:</h3> A prospective observational study was conducted in a Dutch rheumatology outpatient clinic in a hospital specialized in movement and posture. Adult patients with a recent clinical diagnosis of RA initiating MTX treatment between March and June 2023 were invited to participate. An interview guide based on the New Medicines Service was used to question patients about experienced DRPs at 2, 6 and 12 weeks after treatment start by phone [2]. DRPs were categorized using a classification system for patient-reported DRPs as applied by Haegens et al [3]. Data was analysed descriptively. <h3>Results:</h3> Fifty patients were included (median age 62 years (IQR 51-68), 66% female, 38% RF positive, 44% anti-CCP positive), of which 3 patients discontinued MTX treatment. In total, 302 unique DRPs were reported during the three interviews, with a median of 6 unique DRPs per patient (IQR 3-8). At weeks 2, 6 and 12 respectively, 3 (IQR 2-5), 1 (IQR 0-3) and 1 (IQR 0-2) unique DRPs per patient were reported. Most frequently reported categories of DRPs in all interviews included side effects, information needs and medication concerns (Figure 1). The two most frequently reported unique DRPs per category are shown in Table 1. Overall, the top 5 most reported DRPs were concerns about (long-term) side effects (46%), nausea (44%), fatigue (32%), difficulties with medication adherence (28%), concerns regarding the impact of drug use (24%) and insufficient effect (24%). Twenty-six percent of the DRPs reported at weeks 2 and 6 were unresolved at week 12. Mainly nausea remained unresolved as 53% of the patients who earlier reported nausea still experienced nausea at week 12. <h3>Conclusion:</h3> Patients with RA experience numerous DRPs upon MTX treatment initiation, of which a substantial proportion remains unresolved. Adequate support for patients to solve DRPs as early as possible upon treatment initiation may improve adherence and reduce the burden of drug treatment. <h3>REFERENCES:</h3> [1] Curtis JR, Bykerk VP, Aassi M, Schiff M. Adherence and persistence with methotrexate in rheumatoid arthritis: a systematic review. <i>J Rheumatol</i>. 2016;43(11):1997-2009. [2] Pharmaceutical Services Negotiating Committee (PSNC). New Medicine Service Intervention Interview Schedule 2011. [Internet]. [cited 2024 Jan 5]. Available from: https://www.networks.nhs.uk/nhs-networks/south-central-respiratory-community-of-practice/documents/New_Medicine_Service_guidance_Nov2011.pdf. [3] Haegens LL, Huiskes VJB, Smale EM, Bekker CL, van den Bemt BJF. Drug-related problems reported by patients with rheumatic diseases: an observational study. <i>BMC Rheumatol</i>. 2023;7(1):7. <b>Table 1.</b> Top 2 unique DRPs within each DRP category. *1 patient mentioned nausea twice, from both MTX and hydroxychloroquine. **Some DRPs were reported more than once per patient, therefore no percentage of patients reporting this DRP could be calculated. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>