Where do measures of health, social care and wellbeing fit within a wider measurement framework? Implications for the measurement of quality of life and the identification of bolt-ons

Testing the Psychometric Properties of 9 Bolt-Ons for the EQ-5D-5L in a General Population Sample

OBJECTIVES

We aimed to assess the psychometric performance and added value of 9 existing bolt-ons (breathing problems, cognition, hearing, self-confidence, skin irritation, sleep, social relationships, tiredness, and vision) for the EQ-5D-5L in a general population sample.

METHODS

The EQ-5D-5L, 9 bolt-ons, SF-6Dv1, Patient-Reported Outcomes Measurement Information System (PROMIS)-29+2, PROMIS Global Health, and Satisfaction with Life Scale were completed in an online cross-sectional survey among a general adult population sample in Hungary (n = 1587). The following psychometric properties were tested for the EQ-5D-5L + bolt-on(s): ceiling, divergent and convergent validity, structural validity, known-group validity, and explanatory power.

RESULTS

Adding sleep (30%), tiredness (24%), or vision (21%) substantially reduced the ceiling of the EQ-5D-5L (41%). Cognition, sleep, social relationships, and tiredness correlated with corresponding PROMIS and SF-6D items (rs = ǀ0.32ǀ - ǀ0.73ǀ). All bolt-ons, except cognition and self-confidence, loaded on a different factor from the EQ-5D-5L dimensions. Breathing, hearing, skin irritation, and vision significantly improved known-group validity in relevant health condition groups. The sleep bolt-on improved known-group validity in 9 of 13 chronic health conditions. Tiredness had the largest impact on explaining EQ VAS score variance in 8 of 13 conditions. Hearing and vision improved the ability of the EQ-5D-5L to capture declining health with age, whereas self-confidence and social relationships were valuable for mental health assessment.

CONCLUSIONS

This study established the validity of multiple bolt-ons for the EQ-5D-5L and highlights the usefulness of including relevant bolt-ons in population-based and patient surveys. Our findings inform the further development of these bolt-ons and the bolt-on item selection for clinical studies.

The Measurement Properties of the EQ-HWB and the EQ-HWB-S in Italian Population: A Comparative Study With EQ-5D-5L

OBJECTIVES

The EQ Health and Well-being, EQ-HWB (25-item) and the EQ-HWB-S (9-item), are new generic measures of health and well-being. The purpose of this study was to examine the measurement properties of the EQ-HWB and EQ-HWB-S measures in relation to the EQ-5D-5L among the Italian general population.

METHODS

A cross-sectional survey was conducted from October 2020 to February 2021, followed by secondary analysis of collected data from Italian adults. This analysis included response pattern distributions, correlation strength, and known-group comparison. Known-group comparison was assessed using effect sizes (ES) across health conditions, caregiver status, and social care usage. The EQ-HWB-S index-based score was based on the UK pilot value set, whereas the Italian value set was used for scoring the EQ-5D-5L index.

RESULTS

Out of the 1182 participants, 461 reported having a chronic condition, 185 identified as caregivers, and 42 were social care users. EQ-HWB items (7.5%) showed fewer ceiling effects than EQ-5D-5L items (34.7%). Strong correlations (rs > 0.5) were found between overlapping EQ-HWB and EQ-5D-5L items. EQ-HWB-S and EQ-5D-5L index scores demonstrated similar discrimination based on symptomatic chronic conditions (ES d = 0.68 vs d = 0.71), but EQ-HWB-S had slightly higher ES for social care users (ES d = 0.84 vs d = 0.74).

CONCLUSIONS

Initial evidence supports the validity of EQ-HWB/EQ-HWB-S because outcome measures in the Italian population. EQ-HWB-S performed comparably to EQ-5D-5L among patients and was better in differentiating social care users. A slight decrease in discriminative properties for caregivers was observed when transitioning from EQ-HWB to EQ-HWB-S.

A Comparison of Items and Constructs of Standardized Health-Related Quality of Life and Mental Well-Being Measures

OBJECTIVES

This study aimed to explore the internal constructs of the concepts being measured by EQ-5D-5L (a health-related quality of life measure that can produce preference-based utility values) and the 12-item General Health Questionnaire (GHQ-12, a mental well-being measure) and to understand to what extent the items of EQ-5D-5L and GHQ-12 associate with each other.

METHODS

We used data from 12 701 respondents participating in a Belgian survey in 2022. Correlation coefficients between GHQ-12 and EQ-5D-5L were calculated at both the aggregate and item levels. Multidimensional scaling, exploratory factor analysis, and regression models were performed to investigate the underlying constructs that are associated with the items.

RESULTS

Despite a moderate correlation (0.39) between the EQ-5D-5L and GHQ-12 total scores, only a trivial or weak correlation (<0.3) was observed between the first 4 EQ-5D-5L items and any GHQ-12 item. Multidimensional scaling and exploratory factor analysis showed the first 4 EQ-5D-5L dimensions were clustered together with EuroQol visual analog scale and positively phrased GHQ-12 items were close to each other, whereas EQ-anxiety/depression and negatively phrased GHQ-12 items were grouped with overall life satisfaction. In the regression models, not all GHQ-12 items had a significant coefficient to predict EQ-5D-5L responses.

CONCLUSIONS

To the best of our knowledge, we present the first comparison of items and underlying constructs of GHQ-12 and EQ-5D-5L. The results showed that GHQ-12 can only partially predict the responses of EQ-5D-5L and the 2 instruments measure different constructs. Researchers should carefully consider conceptual legitimacy while applying the mapping technique and consider sensitivity analyses for the mapping estimates.