Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.

A Computer Time Trade-off: A Good Alternative for the Interview Time Trade-off in Rheumatoid Arthritis

Buitinga1,  Laurien, Braakman-Jansen1,  Louise, Taal1,  Erik, van de Laar2,  M.A.F.J.

University of Twente, Enschede, Netherlands
Medisch Spectrum Twente & Universtiy Twente, Enschede


The purpose was to evaluate the test-retest reliability of a computer Time Trade-Off (TTO) (an instrument that measures preferences for health states) in patients with Rheumatoid Arthritis (RA), and to compare the computer with the interview TTO regarding feasibility, agreement, and convergent validity.


A cross-over design was used to compare the computer with the interview TTO. Fifty-nine RA patients participated. Thirty patients completed both TTO measures. Twenty-nine other patients completed the computer TTO twice to examine test-retest reliability. Feasibility was measured by comparing actual and experienced time duration of the TTOs and assessing general experience of the patient. Convergent validity was measured by calculating Spearman's correlation between both TTOs. Agreement between both TTOs was measured by using the Bland-Altman analysis.


Both TTOs were feasible. The computer TTO showed high test-retest reliability (ICC=0.88, 95% CI: 0.75 to 0.94), and high convergent validity (r=0.73) with the interview TTO. Bland-Altman analysis showed a small mean difference (0.06, SD=0.14) between the computer and interview TTO. Limits of agreement were wide (-0.22 to 0.34).


Feasibility and reliability of the computer TTO were good. Convergent validity of the computer TTO was high when the interview was used as validation standard. Agreement between the interview and computer TTO was good at group level, indicated by the small mean difference in utilities between both methods. The computer TTO is a good alternative for measuring utilities in RA.

To cite this abstract, please use the following information:
Buitinga, Laurien, Braakman-Jansen, Louise, Taal, Erik, van de Laar, M.A.F.J.; A Computer Time Trade-off: A Good Alternative for the Interview Time Trade-off in Rheumatoid Arthritis [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1128
DOI: 10.1002/art.26203

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