Estimation of minimally important differences and responder definitions for EORTC QLQ-MY20 scores in multiple myeloma patients.
OBJECTIVES
Thresholds for the minimally important difference (MID) or responder definition (RD) in health-related quality-of-life (HRQoL) scores are required to interpret the impact of an intervention or change in the trajectory of the condition which is meaningful to patients. This study aimed to establish MID and RD for the European Organisation for Research and Treatment of Cancer Quality of Life Multiple Myeloma questionnaire (EORTC QLQ-MY20).


METHODS
A novel mixed-methods approach was applied by utilizing both existing clinical trial data and prospective patient interviews. Anchor-based, distribution-based, and qualitative-based estimates of meaningful change were triangulated to form recommended RDs for each scale of the EORTC QLQ-MY20. Anchor-based MIDs were summarized using weighted correlation.


RESULTS
Recommended MIDs were as follows: Disease Symptoms (DS 10 points), Side Effects of Treatment (SE 10 points), Body Image (BI 13 points), and Future Perspective (FP 9 points). Recommended RDs were as follows: DS (16 improvement; 11 worsening), SE (6 improvement; 9 worsening), BI (33 improvement; 33 worsening), and FP (11 improvement; 11 worsening).


CONCLUSIONS
The study generated estimates of the MID and RD for each scale of the EORTC QLQ-MY20. Published estimates will enable investigators and clinicians to adopt these as standard for interpretation and for hypothesis testing. Consequently, analyses from trials of different interventions can be more comparable.
['Sully|Kate|K|', 'Trigg|Andrew|A|https://orcid.org/0000-0002-1613-8042', 'Bonner|Nicola|N|https://orcid.org/0000-0002-9810-9893', 'Moreno-Koehler|Alejandro|A|', 'Trennery|Claire|C|', 'Shah|Nina|N|https://orcid.org/0000-0002-1971-8173', 'Yucel|Emre|E|https://orcid.org/0000-0002-6036-9526', 'Panjabi|Sumeet|S|', 'Cocks|Kim|K|https://orcid.org/0000-0003-2595-708X']
D000368:Aged D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D009101:Multiple Myeloma D011446:Prospective Studies D011788:Quality of Life D011795:Surveys and Questionnaires
minimally important difference responder definition EORTC QLQ-MY20 multiple myeloma quality of life meaningful change interpretation guidelines mixed methods qualitative interviews