Evaluation of the Late Life Disability Instrument in the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) Study
Rejeski, W. Jack
Ip, Edward H.
Katula, Jeff A.
Jette, Alan M.
Studenski, Stephanie A.
Blair, Steven N.
Miller, Michael E.
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Citation (published version)Hsu, Fang-Chi, W Jack Rejeski, Edward H Ip, Jeff A Katula, Roger Fielding, Alan M Jette, Stephanie A Studenski, Steven N Blair, Michael E Miller. "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. (2010)
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 Interventions 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. TRIAL REGISTRATION. The protocol of LIFE-P is consistent with the principles of the Declaration of Helsinki and is registered at http://www.ClinicalTrials.gov (registration # NCT00116194).
RightsCopyright 2010 Hsu et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.