Background: The late life disability instrument (LLDI) was developed to assess limitations in instrumental and management roles using a small and restricted sample. In this paper we examine the measurement properties of the LLDI using data from the Lifestyle Intervention and Independence for Elders Pilot (Life-P) study.
Methods: LIFE-P participants, aged 70-89 years, were at elevated risk of disability. The 424 participants were enrolled at the Cooper Institute, Stanford University, University of Pittsburgh, and Wake Forest University. Physical activity and successful aging health education interventions were compared after 12-months of follow-up. Using factor analysis, we determined whether the LLDI's factor structure was comparable with that reported previously. We further examined how each item related to measured disability using item response theory (IRT).
Results: The factor structure for the limitation domain within the LLDI in the LIFE-P study did not corroborate previous findings. However, the factor structure using the abbreviated version was supported. Social and personal role factors were identified. IRT analysis revealed that each item in the social role factor provided a similar level of information, whereas the items in the personal role factor tended to provide different levels of information.
Conclusions: Within the context of community-based clinical intervention research in aged populations, an abbreviated version of the LLDI performed better than the full 16-item version. In addition, the personal subscale would benefit from additional research using IRT.
Published in Health and Quality of Life Outcomes, Volume 8, Issue 115, 2010, pages 1-10.
Hsu, F-C., Rejeski, W. J., Ip, E. H., Katula, J. A., Fielding, R., Jette, A. M., ... Miller, M. E. (2010). Evaluation of the late life disability instrument in the lifestyle interventions and independence for elders pilot (LIFE-P) study. Health and Quality of Life Outcomes, 8(115), 1-10.
© Health and Quality of Life Outcomes, 2010, BioMed Central