Validity, feasibility and acceptability of time trade-off and standard gamble assessments in health valuation studies: a study in a multiethnic Asian population in Singapore.
OBJECTIVE
To assess the validity, feasibility and acceptability of standard gamble (SG) and time trade-off (TTO) assessments in a multiethnic Asian population.


METHODS
Through in-depth interviews performed among Chinese, Malay, and Indian Singaporeans (education >or= 6 years), we assessed validity of SG/TTO methods for eliciting health preferences by hypothesizing that 1) SG/TTO scores for three hypothetical health states (HS) would exhibit ranked order (decreasing scores with worse HS); and 2) more subjects would rate the most severe HS as worse than dead. Subjects also evaluated feasibility and acceptability of SG/TTO using a 10-point visual analog scale (VAS) and open-ended questions. Ratings were compared using Kruskal-Wallis, Wilcoxon signed-rank tests or tests of proportions.


RESULTS



RESULTS
In 62 subjects (90% response rate), as hypothesized, SG and TTO scores exhibited ranked order with increasing HS severity (SG: 0.85, 0.08, -19.00; TTO: 0.85, 0.00, -0.18). More subjects rated the most severe HS as worse than dead (SG: 8%, 39%, 59%; TTO: 8%, 45% and 62%).


RESULTS
Subjects felt SG and TTO were easy to understand (median VAS scores: 8.0 vs. 8.0, P = 0.87) and to complete (8.0 vs. 8.0, P = 0.84). Acceptability: SG and TTO were well accepted, with TTO less so than SG (median [interquartile range] offensiveness: 2.0 [0, 4.0] vs. 2.0 [0, 3.0], P = 0.045). Overall, subjects did not have a clear preference for SG/TTO (50% vs. 45%, P = 0.70).


CONCLUSIONS
This study suggests the validity, feasibility and acceptability of SG and TTO for population-based HS valuation studies in a multiethnic Asian population.
Wee
Hwee-Lin
HL
Department of Rheumatology & Immunology, Singapore General Hospital, Singapore.
Li
Shu-Chuen
SC
Xie
Feng
F
Zhang
Xu-Hao
XH
Luo
Nan
N
Feeny
David
D
Cheung
Yin-Bun
YB
Machin
David
D
Fong
Kok-Yong
KY
Thumboo
Julian
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000523:psychology* / Q000706:statistics & numerical data; D002681:China / Q000208:ethnology; D018864:Cultural Diversity; D005240:Feasibility Studies; D005260:Female; D006304:Health Status; D006801:Humans; D007194:India / Q000208:ethnology; D007407:Interviews as Topic; D008296:Malaysia / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011788:Quality of Life; D012846:Singapore; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires