Reference bias: presentation of extreme health states prior to eq-vas improves health-related quality of life scores. A randomised cross-over trial

McPhail, Steven, Beller, Elaine and Haines, Terry (2010) Reference bias: presentation of extreme health states prior to eq-vas improves health-related quality of life scores. A randomised cross-over trial. Health and Quality of Life Outcomes, 8 146: 1-11. doi:10.1186/1477-7525-8-146


Author McPhail, Steven
Beller, Elaine
Haines, Terry
Title Reference bias: presentation of extreme health states prior to eq-vas improves health-related quality of life scores. A randomised cross-over trial
Journal name Health and Quality of Life Outcomes   Check publisher's open access policy
ISSN 1477-7525
Publication date 2010-12-01
Sub-type Article (original research)
DOI 10.1186/1477-7525-8-146
Open Access Status DOI
Volume 8
Issue 146
Start page 1
End page 11
Total pages 11
Place of publication London, United Kingdom
Publisher BioMed Central
Language eng
Subject 2739 Public Health, Environmental and Occupational Health
Formatted abstract
Background: Clinical practice and clinical research has made a concerted effort to move beyond the use of clinical indicators alone and embrace patient focused care through the use of patient reported outcomes such as health-related quality of life. However, unless patients give consistent consideration to the health states that give meaning to measurement scales used to evaluate these constructs, longitudinal comparison of these measures may be invalid. This study aimed to investigate whether patients give consideration to a standard health state rating scale (EQ-VAS) and whether consideration of good and poor health state descriptors immediately changes their self-report.

Methods: A randomised crossover trial was implemented amongst hospitalised older adults (n = 151). Patients were asked to consider descriptions of extremely good (Description-A) and poor (Description-B) health states. The EQ-VAS was administered as a self-report at baseline, after the first descriptors (A or B), then again after the remaining descriptors (B or A respectively). At baseline patients were also asked if they had considered either EQ-VAS anchors.

Results: Overall 106/151 (70%) participants changed their self-evaluation by ≥5 points on the 100 point VAS, with a mean (SD) change of +4.5 (12) points (p < 0.001). A total of 74/151 (49%) participants did not consider the best health VAS anchor, of the 77 who did 59 (77%) thought the good health descriptors were more extreme (better) then they had previously considered. Similarly 85/151 (66%) participants did not consider the worst health anchor of the 66 who did 63 (95%) thought the poor health descriptors were more extreme (worse) then they had previously considered.

Conclusions: Health state self-reports may not be well considered. An immediate significant shift in response can be elicited by exposure to a mere description of an extreme health state despite no actual change in underlying health state occurring. Caution should be exercised in research and clinical settings when interpreting subjective patient reported outcomes that are dependent on brief anchors for meaning.

Trial Registration: Australian and New Zealand Clinical Trials Registry (#ACTRN12607000606482) http://www.anzctr.org.au
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Health and Rehabilitation Sciences Publications
 
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