Framing of mobility items: a source of poor agreement between preference-based health-related quality of life instruments in a population of individuals receiving assisted ventilation

Liam M. Hannan*, David G. T. Whitehurst, Stirling Bryan, Jeremy D. Road, Christine F. McDonald, David J. Berlowitz, Mark E. Howard

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Purpose: To explore the influence of descriptive differences in items evaluating mobility on index scores generated from two generic preference-based health-related quality of life (HRQoL) instruments.

Methods: The study examined cross-sectional data from a postal survey of individuals receiving assisted ventilation in two state/province-wide home mechanical ventilation services, one in British Columbia, Canada and the other in Victoria, Australia. The Assessment of Quality of Life 8-dimension (AQoL-8D) and the EQ-5D-5L were included in the data collection. Graphical illustrations, descriptive statistics, and measures of agreement [intraclass correlation coefficients (ICCs) and Bland–Altman plots] were examined using index scores derived from both instruments. Analyses were performed on the full sample as well as subgroups defined according to respondents’ self-reported ability to walk.

Results: Of 868 individuals receiving assisted ventilation, 481 (55.4%) completed the questionnaire. Mean index scores were 0.581 (AQoL-8D) and 0.566 (EQ-5D-5L) with ‘moderate’ agreement demonstrated between the two instruments (ICC = 0.642). One hundred fifty-nine (33.1%) reported level 5 (‘I am unable to walk about’) on the EQ-5D-5L Mobility item. The walking status of respondents had a marked influence on the comparability of index scores, with a larger mean difference (0.206) and ‘slight’ agreement (ICC = 0.386) observed when the non-ambulant subgroup was evaluated separately.

Conclusions: This study provides further evidence that between-measure discrepancies between preference-based HRQoL instruments are related in part to the framing of mobility-related items. Longitudinal studies are necessary to determine the responsiveness of preference-based HRQoL instruments in cohorts that include non-ambulant individuals.
Original languageEnglish
Pages (from-to)1493-1505
Number of pages13
JournalQuality of Life Research
Volume26
Issue number6
Early online date2 Mar 2017
DOIs
Publication statusPublished - Jun 2017

Keywords

  • AQoL-8D
  • EQ-5D-5L
  • Mobility
  • Quality of life
  • Respiratory insufficiency
  • Non-invasive ventilation

Cite this