Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement
The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.
Creation of a Short Version of the Valued Life Activities Questionnaire (S-VLA)
Katz1, Patricia, Allen1, Diane D., Hassett2, Afton L., Li3, Tracy, Maclean3, R.
Disability in valued life activities (VLAs), defined as the wide range of activities that individuals may perform on a daily basis, has been strongly linked to psychological well-being, satisfaction with function, and quality of life among individuals with rheumatoid arthritis (RA). Need for accommodations (ACCs) in VLAs predicts progression of disability in RA. The current VLA disability questionnaire queries difficulty in 33 activities, with 4 follow-up questions for each activity regarding ACCs. Difficulty is rated on a 5-point scale from no difficulty (0) to unable to perform the activity (4). A scoring method incorporating use of ACCs has been developed. Our objective was to create a short version of the questionnaire, incorporating use of ACCs.
Data from 2 years' administration of the long form VLA questionnaire (L-VLA) in a longitudinal cohort of individuals with RA were used (n=449, 421). Analyses were first conducted with Year 1 data and then validated with Year 2 data. Item response analyses using ConQuest were performed. Items were deleted based on misfit (weighted mean square statistic <0.75 or >1.34 AND t-statistics <-2 or >+2), logit values that duplicated information provided by other items providing information at similar logit values, and substantive considerations. Psychometric properties of the short version (S-VLA) were compared to those of the L-VLA.
Partial credit and rating scale models were both tested; the partial credit model had fewer item and step misfits (G2 likelihood ratio = 623.881, p<.0001). The scoring range was expanded to 05 to account for use of ACCs (0=no difficulty, no ACCs; 1=no difficulty, with ACCs; other difficulty ratings increased by 1 to account for additional category). Deletions were progressive, resulting in a 21-item version, a 14-item version, and 4 12-item versions. A 14-activity version of the VLA questionnaire, with 1 follow-up question for each regarding ACCs, was selected. The S-VLA had 0 misfitting steps; 2 items had potential misfit but were retained for both substantive reasons and to provide logit spread. Correlation between L-VLA and S-VLA scores was.97; correlations of the L-VLA and S-VLA with other measures of functioning and RA impact were similar (Table). Analyses were confirmed in Year 2 data.
|EAP reliability||Cronbach's a||HAQ||Overall rating of RA impact 0100||RA affects things you NEED to do||RA affects things you LIKE to do|
A short form of the VLA disability questionnaire has been developed. The S-VLA appears to be reliable and valid, and can provide a brief assessment of disability in a broad range of life activities. Since it includes the broad range of activities, it may be more sensitive to change than other measures of functioning such as the HAQ and may appear more relevant to individuals with RA.
To cite this abstract, please use the following information:
Katz, Patricia, Allen, Diane D., Hassett, Afton L., Li, Tracy, Maclean, R.; Creation of a Short Version of the Valued Life Activities Questionnaire (S-VLA) [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1126