Validation of an Instrument for Measuring Adherence to Treatment With Immunomodulators in Patients With Multiple Myeloma

Abstract

Background: Validate the Treatment Adherence Measure (TAM) instrument in outpatients with MM concerning construct validity, reliability and the ceiling and floor effects.Methods: This cross-sectional study included patients diagnosed with MM previously treated with an immunomodulator for at least one month, aged 18 or over, and followed-up in the investigated outpatient clinics. Adherence to immunomodulators was measured by TAM. The TAM’s reliability was assessed using Cronbach’s alpha; The association between adherence and health-related quality of life was investigated to analyze the divergent and convergent construct, measured by the Quality of Life Questionnaire core (QLQ-C30) and the Quality of Life Questionnaire Multiple Myeloma module (QLQ-MY20). The presence of a ceiling or floor effect in the TAM was also analyzed.Results: Eighty-four patients were included in the study, achieving 97.6% adherence. Cronbach’s alpha was 0.41, and the hypothesis of convergent construct validity was confirmed, with statistical significance, in contrast to the hypothesis of divergent construct validity. The presence of the ceiling effect in TAM suggested that this instrument does not allow changes to be detected in individuals concerning adherence to IMiDs.Conclusion: TAM instrument did not show satisfactory validity and reliability to measure MM’s adherence. MM patients treated at oncohematological outpatient clinics in a metropolitan region of southeastern Brazil showed high adherence to IMiDs.

Validation of a scale to assess adherence to oral chemotherapy based on the experiences of patients and healthcare professionals (EXPAD-ANEO)

“…In a more recent study, the validation of the Treatment Adherence Measure (TAM) ( Silveira et al, 2021 ) in outpatients with multiple myeloma was unsatisfactory. That study reported very high adherence to treatment and a tendency to extreme responses, as in our study.…”

“…The first factor of our instrument distinguishes it from other adherence scales, and provides the opportunity to explore patients' thoughts, beliefs and expectations, and how these variables correlate to more or less adherent behavior. In addition, we responded to the floor/ceiling effect identified during the validation process by dichotomizing the responses (Yes/No), as in other published studies (Silveira et al, 2021;da Silva Carvalho et al, 2010). Criterion validity is important because it compares our results with the gold standard.…”

“…Two studies conducted in Spain reported adherence rates ranging from 72% to 79% ( Olivera-Fernandez et al, 2014 ; Fernández-Ribeiro et al, 2017 ). Most tools currently in use are validated for other chronic diseases ( Silveira et al, 2021 ). In people with cancer, one of the most frequently used tools is the Morisky-Green test ( Huang et al, 2016 ).…”

“…However, there are few initiatives in the literature to validate adherence scales or questionnaires in OAA users ( Claros et al, 2019 ; Huang et al, 2016 ). Some studies have included very small patient samples ( Peng and Wu, 2020 ), and the results of others have shown limited psychometric properties ( Silveira et al, 2021 ). Furthermore, there are currently no references in the Spanish population, although research has shown that social and cultural characteristics may directly influence the barriers to and facilitators of adherence to OAAs ( Irwin and Johnson, 2015 ).…”

A prospective study of adherence to lenalidomide for multiple myeloma using Medication Event Monitoring System (MEMS) caps

“…Thus, MPR likely leads to an underestimation of lenalidomide adherence. Patient-reported adherence has been used as an alternative measure but is also not sufficiently reliable [8,9]. One recent study in Germany combined patient interviews with prescription data, survey of attending physicians, and caregiver interviews [10].…”