EMPIRICAL VALIDITY OF CANADIAN-WEIGHTED HEALTH UTILITIES FOR THE VR-12 IN PATIENTS WITH LIFE-LIMITING ILLNESS AND THEIR FAMILY CAREGIVERS
Author(s)
MUNTASIR RAHMAN, MS1, Richard Sawatzky, Ph.D.2, David G. Whitehurst, PhD3;
1Simon Fraser University, Faculty of Health Sciences, Burnaby, BC, Canada, 2Trinity Western University, Langley, BC, Canada, 3Simon Fraser University, Burnaby, BC, Canada
1Simon Fraser University, Faculty of Health Sciences, Burnaby, BC, Canada, 2Trinity Western University, Langley, BC, Canada, 3Simon Fraser University, Burnaby, BC, Canada
OBJECTIVES: The Veterans RAND 12-Item Health Survey (VR-12) is a generic patient-reported outcome measure designed to assess health-related quality-of-life. Since 2023, VR-12 responses can also be used to derive health utilities reflecting Canadian population preferences. This study examines convergent validity, discriminant validity, and sensitivity-to-change of VR-12 health utilities in the context of older Canadians with life-limiting illnesses and their family caregivers.
METHODS: Data come from a randomized controlled trial comprising patients (n=331) receiving home-based care and their caregivers (n=111), with outcomes collected at two-month intervals over a year. Pertinent data include the VR-12 and sociodemographics, the McGill Quality of Life and Edmonton Symptom Assessment System (patients), and the Quality of Life in Life-Threatening Illness (caregivers). Analyses-conducted separately for patients and caregivers-explored: (i) convergent validity (Spearman’s rank correlation); (ii) discriminant validity, based on 21 ‘strong’ and 11 ‘exploratory’ hypothesized constructs; and (iii) sensitivity-to-change, using distributional methods to categorise participants as improved, stable, or declined based on two quality-of-life anchors.
RESULTS: Mean baseline health utility scores were 0.42 (SD 0.27) for patients and 0.62 (SD 0.28) for caregivers. Observed associations followed theoretically expected patterns in direction and relative strength, with strongest correlations for physical, existential, and psychological domains in patients, and for caregivers’ own condition. Seventeen (of 21) and seven (of 11) constructs were confirmed for patients and caregivers, respectively. Sensitivity-to-change analyses showed significant differences in mean change scores across the three categories (improved, stable, or declined). Preliminary effect-size metrics (Cohen’s d and standardized response mean) and AUC-ROC analyses indicate moderate discriminative ability.
CONCLUSIONS: Validity evidence indicates that the VR-12 provides sufficient support for measuring health utility values for older Canadians with life-limiting illnesses and their caregivers. These findings add to the body of evidence to support the suitability of VR-12 health utilities - and wider VR-12 use - in economic evaluations.
METHODS: Data come from a randomized controlled trial comprising patients (n=331) receiving home-based care and their caregivers (n=111), with outcomes collected at two-month intervals over a year. Pertinent data include the VR-12 and sociodemographics, the McGill Quality of Life and Edmonton Symptom Assessment System (patients), and the Quality of Life in Life-Threatening Illness (caregivers). Analyses-conducted separately for patients and caregivers-explored: (i) convergent validity (Spearman’s rank correlation); (ii) discriminant validity, based on 21 ‘strong’ and 11 ‘exploratory’ hypothesized constructs; and (iii) sensitivity-to-change, using distributional methods to categorise participants as improved, stable, or declined based on two quality-of-life anchors.
RESULTS: Mean baseline health utility scores were 0.42 (SD 0.27) for patients and 0.62 (SD 0.28) for caregivers. Observed associations followed theoretically expected patterns in direction and relative strength, with strongest correlations for physical, existential, and psychological domains in patients, and for caregivers’ own condition. Seventeen (of 21) and seven (of 11) constructs were confirmed for patients and caregivers, respectively. Sensitivity-to-change analyses showed significant differences in mean change scores across the three categories (improved, stable, or declined). Preliminary effect-size metrics (Cohen’s d and standardized response mean) and AUC-ROC analyses indicate moderate discriminative ability.
CONCLUSIONS: Validity evidence indicates that the VR-12 provides sufficient support for measuring health utility values for older Canadians with life-limiting illnesses and their caregivers. These findings add to the body of evidence to support the suitability of VR-12 health utilities - and wider VR-12 use - in economic evaluations.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
P28
Topic
Patient-Centered Research
Topic Subcategory
Health State Utilities, Instrument Development, Validation, & Translation, Patient-reported Outcomes & Quality of Life Outcomes
Disease
No Additional Disease & Conditions/Specialized Treatment Areas