Validity and reliability of the QLQ-MY20 module for assessing the health-related quality of life in Brazilians with multiple myeloma

Abstract

Purpose Multiple myeloma (MM) is a rare but treatable hematological cancer, which makes the health-related quality of life (HRQoL) an important patient-report outcome measure in clinical studies. The Quality of Life Questionnaire Multiple Myeloma Module (QLQ-MY20) was developed by the European Organization for Research and Treatment of Cancer (EORTC) to measure HRQoL in people with MM. However, the Brazilian Portuguese version of QLQ-MY20 has not yet been validated for Brazil. This study aimed to evaluate the validity and reliability of the instrument for application in Brazilian patients with MM. Methods This is a cross-sectional methodological study with patients seen in health services in Belo Horizonte, Brazil. The variables were collected through face-to-face interviews with the QLQ-MY20 instrument and complemented with data from medical records. Content validity analyses (content validity coefficient [CVC]; correctness ratio), convergent and divergent validity (Spearman’s correlation coefficient [CC]), internal consistency, and temporal reproducibility (test–retest; intraclass correlation coefficient [ICC]) were performed. Results 225 patients were included and 71.1% were older than 60. The analysis of the judging committee showed adequate content validity. We observed mainly a good internal consistency of the items and good discrimination power in the convergent and divergent validity. High ICC values were observed through the test–retest, and there was no difference in the scores between the two moments, which shows good temporal stability of the instrument. Conclusion The study allowed us to conclude that the Brazilian version of the QLQ-MY20 module is valid and reliable, and thus suitable for application in Brazilians living with MM.