Impact of secondary health conditions on the quality of life and wellbeing of Canadians living with spinal cord injury: A comparison of preference-weighted index scores derived from generic standardized instruments.

Context/objectives: To compare the assessment of the impact of secondary health conditions (SHCs) on the quality of life and wellbeing of Canadians living with spinal cord injury (SCI) using four preference-based outcome measures.

Design: Secondary analysis of data from a cross-sectional, online survey.

Setting: Community.

Participants: Community-dwelling adults (n = 364) living with traumatic or non-traumatic spinal cord injury at least one year post-injury (70% at least 10 years post-injury).

Outcome measures: A modified version of the Spinal Cord Injury Secondary Conditions Scale (SCI-SCS); three health-related instruments (EQ-5D-5L, Health Utilities Index Mark 3 (HUI3), and the Assessment of Quality of Life 8-dimension questionnaire (AQoL-8D)) and a capability wellbeing instrument (ICEpop CAPability measure for Adults (ICECAP-A)).

Results: Across unadjusted and controlled analyses (i.e. controlling for associations between index scores and sociodemographic and impairment characteristics), trends were observed that identified lower levels of quality of life/wellbeing with higher problem ratings for each of the SHCs. Despite the trends, there was considerable variation in mean index scores across instruments, with HUI3 scores the lowest of the health-related instruments and ICECAP-A scores the highest overall. Respiratory problems, depression/mood problems, pressure sores, and autonomic dysreflexia were associated with the lowest levels of quality of life and wellbeing.

Conclusions: Higher problem ratings for SHCs are negatively associated with scores derived from preference-based quality of life and wellbeing instruments. Variation in index scores across instruments - including across the health-related instruments alone - highlights the critical importance of assessing the relative merits of preference-based instruments when using (or considering using) these instruments/estimates in comparative effectiveness research and economic evaluation.