Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

Ph.D. in Pharmaceutical Sciences


Pharmacy Administration

First Advisor

Rahul Khanna

Second Advisor

Glenn Philips

Third Advisor

Matthew Strum

Relational Format



OBJECTIVES The study objectives were to evaluate psychometric properties of the EuroQoL–five–dimensional questionnaire (EQ–5D–3L) among caregivers of individuals with multiple sclerosis (MS), assess caregiver utilities and determine predictors of utilities, and compare caregiver utilities obtained from the EQ–5D–3L and the SF–6D. METHODS A web–based survey was administered to MS caregivers via Qualtrics survey software using assistance from a MS patient registry– North American Research Committee on MS (NARCOMS). Measurement properties including convergent, discriminant, and known–groups validity, reliability, and ceiling and floors effects of the EQ–5D–3L were tested. Caregiver health utilities were estimated using the EQ–5D–3L and compared with population norms; and predictors of utilities were identified using path analysis, a form of structural equational modelling (SEM). Correlational analysis was conducted to assess domain–level agreement of EQ–5D–3L and SF–6D utilities. Scale level agreement was assessed by intra–class correlation coefficient (ICC), and Bland–Altman plot. Multivariable linear regression was used to identify determinants of discordance between EQ–5D–3L and SF–6D utilities. RESULTS The study sample comprised of 215 MS caregivers. The EQ–5D–3L demonstrated acceptable convergent, discriminant, and known–groups validity and reliability. Ceiling effects were present and floor effects were non–existent. Utilities among MS caregivers (aged 18–44 years) were lower than population norms (0.83 vs. 0.91). Caregiver burden (objective and subjective), care recipient disability status, and avoidance and critical coping influenced caregiver utilities. The mean utilities were 0.83 and 0.74 for EQ–5D–3L and SF–6D, respectively. Discernable differences between utility distributions were observed. The measures appeared to agree at the domain–level; however, a scale–level agreement was lacking. Mean discordance of 0.09 was noted, and care recipient disability, family income, and caregiver marital status significantly predicted discordance between EQ–5D–3L and SF–6D. CONCLUSIONS The study findings revealed acceptable psychometric profile of the EQ–5D–3L among MS caregivers. Lower utilities among MS caregivers point towards the detrimental impact of caregiving. Factors affecting caregiver utilities identified in this study can be utilized to inform the design of intervention programs/support services for MS caregivers. Discordance between EQ–5D–3L and SF–6D utilities suggest that these estimates may not be interchangeably used to calculate quality–adjusted life year (QALY) estimates for resource allocation decisions pertaining to MS treatments.



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