The development and validation of a Patient-Perceived Methotrexate Intolerance Scale for use in adult rheumatoid arthritis patients

Elizabeth Salt, Amanda Wiggins, Kristine Lohr, Leslie Crofford, Jamie Studts, W. Benjamin Nowell, Joseph C. Cappelleri, Mary Kay Rayens

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Introduction/Objective: To develop a scale to measure methotrexate intolerance for use in adult rheumatoid arthritis (RA) patients and to describe its psychometric properties. Methods: A three-phase study was conducted. During Phase 1, we conducted individual interviews with RA patients (n = 14) to inform our item development process. During Phase 2, we asked for RA patients' (n = 10) feedback on item readability, clarity and the scale's ability to measure methotrexate intolerance. During Phase 3, we had patients with RA (n = 204) complete the scale to develop a final version and to describe the scale's internal validity (Cronbach’s alpha), test–retest reliability (intra-class correlation coefficients), construct validity and discriminant validity and the ability of the scale to discriminate between past and present methotrexate users. Results: The newly developed, weighted scale (Patient-Perceived Methotrexate Intolerance Scale [PPMIS]) includes four subscales: Methotrexate Benefits, Methotrexate Risks-Side Effect Considerations, RA Risks and Methotrexate Risks-Willingness to Take Methotrexate Despite Risks. Cronbach's alpha ranged from 0.79 to 0.94. Test–retest reliability at 2 weeks was 0.73–0.88. Construct validity was supported with significant logical relationships between subscale scores and the existing methotrexate intolerance scale and past/present methotrexate use. The PPMIS was able to correctly classify RA patients as a past versus present methotrexate user 77% of the time. At the cut point of 3.29, the sensitivity of the PPMIS is 74% and specificity is 72% to correctly classify patients into past/present methotrexate use. Conclusion: This is the first known scale with favourable measurement properties to evaluate methotrexate intolerance using a patient-centred perspective.

Original languageEnglish
Pages (from-to)529-540
Number of pages12
JournalMusculoskeletal Care
Issue number3
StatePublished - Sep 2022

Bibliographical note

Funding Information:
The authors would like to acknowledge the rheumatology clinic staff and participants that made this project possible. This study was sponsored by Pfizer, Inc.

Publisher Copyright:
© 2021 John Wiley & Sons Ltd.


  • methotrexate intolerance
  • psychometric evaluation
  • rheumatoid arthritis
  • scale development

ASJC Scopus subject areas

  • Rheumatology
  • Chiropractic
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation
  • Nursing (miscellaneous)


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