The psychometric properties of the EQ-HWB and EQ-HWB-S in patients with breast cancer: a comparative analysis with EQ-5D-5L, FACT-8D, and SWEMWBS

Objectives: The EQ Health and Wellbeing (EQ-HWB) is a new generic measure that captures constructs beyond health-related quality of life, with a 25-item long form and a shorter 9-item version (EQ-HWB-S). This study aimed to assess the psychometric performance of both versions in breast cancer, which is the most prevalent cancer worldwide, and compare them with other instruments.

Methods: A longitudinal survey in Indonesia (2023-2024) with 300 female patients used the EQ-HWB, 5-level EQ-5D (EQ-5D-5L), Functional Assessment of Cancer Therapy – General (from which Functional Assessment of Cancer Therapy Eight Dimension [FACT-8D] was derived), and Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS, from which the Short WEMWBS was derived). Distributional characteristics, convergent validity, known-group validity (Student's t test or analysis of variance), test-retest reliability, and responsiveness were assessed.

Results: All patients reported problems in at least 1 EQ-HWB item. The EQ-HWB-S index (11%) had a lower ceiling than the EQ-5D-5L (35%) and the Short WEMWBS (15.3%), but not the FACT-8D (5%). EQ-HWB-S index values correlated strongly with EQ-5D-5L (r = 0.73) and FACT-8D index values (r = 0.70), whereas EQ-HWB level sum scores correlated strongly with Functional Assessment of Cancer Therapy – General (r = 0.69) and moderately with WEMWBS (r = 0.49). The EQ-HWB and EQ-HWB-S discriminated across known groups comparably with the EQ-5D-5L and FACT-8D with large effect sizes according to EuroQol visual analog scale groups, number of symptoms, and general health and exhibited excellent instrument-level test-retest reliability (intraclass correlations, 0.79-0.83) and acceptable responsiveness (standardized response means, |0.24| to |0.97|).

Conclusions: This study represents one of the first validations of the EQ-HWB and EQ-HWB-S in any clinical population. Both instrument versions demonstrate robust psychometric performance. The EQ-HWB-S can be recommended to inform resource allocation decisions of breast cancer treatments.