Methotrexate Intolerance: A Complex Belief System

Patient trust, quality communication, and medication adherence in rheumatoid arthritis patients highly affected by social determinants of health

INTRODUCTION

Because medication adherence is essential to the management of rheumatoid arthritis (RA), identifying (1) subgroups at high risk for low medication adherence and (2) modifiable factors potentially contributing to low adherence can impact patient outcomes. This study aims to describe the relationships between anxiety, trust in the provider, quality patient-provider communication, fatigue, RA knowledge, adverse medication effects, disease activity, RA medications, disease duration, patient satisfaction, and medication intolerance and cluster factors to differentiate RA-patient subgroups.

METHODS

This observational study used correlation analysis, linear regression, and cluster analysis with determination decisions based on Schwarz's Bayesian Criterion.

RESULTS

Medication adherence was higher in non-Hispanic, White participants, inversely correlated with disease activity and pain intensity, and positively correlated with trust in the provider. Patient satisfaction was higher among those with a shorter time since diagnosis, and was negatively associated with disease activity, pain intensity and interference, fatigue, and anxiety. It was positively associated with RA knowledge, trust in provider and quality of patient-provider communication. Medication intolerance differed by disease duration and was positively correlated with disease activity, pain interference, and fatigue. Of the two clusters, Cluster 1 participants had greater medication adherence and patient satisfaction, and lower medication intolerance. They were of higher income, employed, and non-Hispanic, White persons with a shorter disease duration and lower perceived pain intensity/interference, fatigue, and anxiety. They were more knowledgeable about RA with higher trust in their provider and perceived quality of patient-provider communication.

DISCUSSION/CONCLUSION

A low medication adherence RA-patient subgroup-highly affected by social determinants of health and with unique relational and clinical characteristics was identified.

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

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.