[PMC62] Online administration of the time trade-off: a case-study among people with restless legs syndrome

[PMC62] Online administration of the time trade-off: a case-study among people with restless legs syndrome

2009 Value in health

Aballea, S. | Quilici, S. | Roiz, J. | Volume: 12, Issue: 7, Pages: A398,

OBJECTIVES: Time trade-off (TTO) utilities are traditionally elicited through faceto-face
interviews, but these may be costly and time-consuming. We recruited a sample
of restless-legs syndrome (RLS) sufferers using an online panel and administered an
online version of TTO. METHODS: Members of a UK online marketing research
panel were invited to participate, subject to confirmation of RLS diagnosis. The
recruitment target was a minimum of 50 subjects in each of 4 severity categories based
on the International Restless Legs Syndrome (IRLS) score. The TTO interface was
adapted from a widely used, validated protocol for face-to-face administration. We
explored associations between self-rated health according to IRLS, EQ-5D (UK tariff)
and the online TTO. RESULTS: Over 15 days, 287 eligible participants (57, 90, 90
and 50 in mild, moderate, severe and very severe categories respectively) were
recruited. Mean EQ-5D utilities by severity category were 0.80, 0.67, 0.51 and 0.29.
275 participants agreed to complete the TTO. Twenty-four percent were unwilling to
sacrifice any life expectancy in their current state of health although they preferred a
life in full health for a similar duration. Mean TTO utilities by severity category were
0.83, 0.82, 0.75 and 0.56. The correlation between EQ-5D and TTO utilities was
0.354 (p 0.0001). TTO utilities were associated with EQ-5D utilities independently
of IRLS score. Neither EQ-5D nor TTO utilities were significantly associated with age
or gender, after controlling for IRLS score. Social class was significantly associated
with EQ-5D, but not with TTO. CONCLUSIONS: Online recruitment enabled rapid
recruitment of subjects with RLS. Correlations between TTO utilities and other variables
were consistent with expectations, but the number of non-traders seemed high.
Comparative studies with face-to-face TTO would be desirable, as the online approach
seems an attractive solution to allow primary utility elicitation when time or cost
constraints preclude a face-to-face survey.