An international field study of the reliability and validity of a disease-specific questionnaire module (the QLQ-MY20) in assessing the quality of life of patients with multiple myeloma.

ABSTRACT

AIM: To test the reliability, validity and sensitivity of the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-MY24 questionnaire, designed to assess the quality of life of myeloma patients with the QLQ-C30. METHODS: The study was carried out through the EORTC Quality of Life Group using clinical trials in seven countries. All trials used the QLQ-C30 and QLQ-MY24 at baseline and a follow-up timepoint. RESULTS: Two hundred and forty patients participated. The questionnaires were acceptable to patients. The hypothesised scale structure (disease symptoms, side-effects, body image and future perspective) was confirmed by multi-trait scaling, internal consistency and correlation analysis. Most scales demonstrated sensitivity to change and discriminated between clinically different patients. The social support scale (4 items) was removed due to observed ceiling effects. CONCLUSION: The final questionnaire contains 20 items, QLQ-MY20, and is a reliable and valid instrument recommended for use with the QLQ-C30 in myeloma patients.