Estimating the minimally important difference for the EQ-5D-5L and EORTC QLQ-C30 in cancer.

Bourke, Siobhan; Bennett, Bryan; Oluboyede, Yemi; Li, Tara; Longworth, Louise; O'Sullivan, Sian Bissell; Braverman, Julia; Soare, Ioana-Alexandra; Shaw, James W.

Background: The minimal important difference (MID) is a useful tool to interpret changes in patients' health-related quality of life. This study aims to estimate MIDs for interpreting within-patient change for both components of the EQ-5D-5L questionnaire [EQ-Visual Analogue Scale (EQ-VAS) and utility index] and domains of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) for cancer patients. Methods: Data were obtained from the Cancer 2015 dataset, a longitudinal cohort of Australian cancer patients. Anchor-based approaches were used to estimate MIDs for the EQ-5D-5L index-based utility index [Australia and the United States (US) tariff sets], EQ-VAS scores, and the EORTC QLQ-C30. Clinical [Eastern Cooperative Oncology Group (ECOG) performance status] and patient-reported (items 29 and 30 of the EORTC QLQ-C30 and the EQ-VAS) anchors were assessed for appropriateness by their correlation strength. Clinical change groups (CCGs) were defined a priori for improvement and deterioration based on estimates used in previous literature. MIDs were estimated via linear regression and distribution-based methods. Results: For the index-based utility scores in Australia, the anchor-defined MID estimates were 0.01 to 0.06 for improvement and − 0.04 to -0.03 for deterioration, with a weighted value of 0.03 for improvement and deterioration. The EQ-VAS MID estimate was 5 points for both improvement and deterioration. For the EORTC QLQ-C30, changes of at least 3.64 (improvement) and − 4.28 (deterioration) units on the physical functioning scale, 6.31 (improvement) and − 7.11 (deterioration) units on the role functioning scale, 4.65 (improvement) and − 3.41 (deterioration) units on the emotional functioning scale, and 5.41 (improvement) and − 5.56 (deterioration) units on the social functioning scale were estimated to be meaningful. Conclusion: This study identified lower MIDs for the EQ-5D-5L utility index, EQ-VAS, and EORTC QLQ-C30 domain scores, than those reported previously. The use of a real-world cancer-specific panel dataset may reflect smaller MID estimates that are more applicable to cancer patients in the clinical practice, rather than using MIDs that have been estimated from clinical trials.

QUALITY of life; SOCIAL skills; CANCER patients; CLINICAL trials; CANCER treatment

Health & Quality of Life Outcomes, 2024, Vol 22, Issue 1, p1

1477-7525

Academic Journal

10.1186/s12955-024-02294-3