TY - JOUR
T1 - Using item response theory to estimate interpretation threshold values for the Frailty Index in community dwelling older adults
AU - Pua, Yong Hao
AU - Terluin, Berend
AU - Tay, Laura
AU - Clark, Ross Allan
AU - Thumboo, Julian
AU - Tay, Ee Ling
AU - Mah, Shi Min
AU - Ng, Yee Sien
N1 - Funding Information: This study is funded by National Medical Research Council Centre Grants ( CGAug16C027 and CGAug16M011 ) and the National Innovation Challenge on Active and Confident Ageing Grant ( MOH/NIC/HAIG04/2017 ). Funding Information: This study is funded by National Medical Research Council Centre Grants (CGAug16C027 and CGAug16M011) and the National Innovation Challenge on Active and Confident Ageing Grant (MOH/NIC/HAIG04/2017).We thank the study participants, staff of the Senior Activity Centres, and Resident Committees in the northeast region of Singapore for their logistical and manpower support. We extend our gratitude to Vanessa Voong Zi Lin from the Sengkang General Hospital Department of Physiotherapy for their contributions towards this project. Publisher Copyright: © 2023 Elsevier B.V.
PY - 2024/2
Y1 - 2024/2
N2 - Background: Although the frailty index (FI) is designed as a continuous measure of frailty, thresholds are often needed to guide its interpretation. This study aimed to introduce and demonstrate the utility of an item response theory (IRT) method in estimating FI interpretation thresholds in community-dwelling adults and to compare them with cutoffs estimated using the receiver operating characteristics (ROC) method. Methods: A sample of 1,149 community-dwelling adults (mean[SD], 68[7] years) participated in this cross-sectional study. Participants completed a multi-domain geriatric screen from which the 40-item FI and 3 clinical anchors were computed – namely, (i)self-reported mobility limitations (SRML), (ii)"fair" or "poor" self-rated health (SRH), and (iii) restricted life-space mobility (RLSM). Participants were classified as having SRML-1 if they responded "Yes" to either of the 2 questions regarding walking and stair climbing difficulty and SRML-2 if they reported having walking and stair climbing difficulty. Participants with a Life Space Assessment score <60 points were classified as having RLSM. Threshold values for all anchor questions were estimated using the IRT method and ROC analysis with Youden criterion. Results: The proportions of participants with SRML-1, SRML-2, Fair/Poor SRH, and RLSM were 21 %, 8 %, 22 %, and 9 %, respectively. The IRT-based thresholds for SRML-2 (0.26), fair/poor SRH (0.29), and RLSM (0.32) were significantly higher than those for SRML-1 (0.18). ROC-based FI cutoffs were significantly lower than IRT-based values for SRML-2, SRH, and RLSM (0.12 to 0.17), and they varied minimally and non-systematically across the anchors. Conclusions: The IRT method identifies biologically plausible FI thresholds that could meaningfully complement and contextualize existing thresholds for defining frailty.
AB - Background: Although the frailty index (FI) is designed as a continuous measure of frailty, thresholds are often needed to guide its interpretation. This study aimed to introduce and demonstrate the utility of an item response theory (IRT) method in estimating FI interpretation thresholds in community-dwelling adults and to compare them with cutoffs estimated using the receiver operating characteristics (ROC) method. Methods: A sample of 1,149 community-dwelling adults (mean[SD], 68[7] years) participated in this cross-sectional study. Participants completed a multi-domain geriatric screen from which the 40-item FI and 3 clinical anchors were computed – namely, (i)self-reported mobility limitations (SRML), (ii)"fair" or "poor" self-rated health (SRH), and (iii) restricted life-space mobility (RLSM). Participants were classified as having SRML-1 if they responded "Yes" to either of the 2 questions regarding walking and stair climbing difficulty and SRML-2 if they reported having walking and stair climbing difficulty. Participants with a Life Space Assessment score <60 points were classified as having RLSM. Threshold values for all anchor questions were estimated using the IRT method and ROC analysis with Youden criterion. Results: The proportions of participants with SRML-1, SRML-2, Fair/Poor SRH, and RLSM were 21 %, 8 %, 22 %, and 9 %, respectively. The IRT-based thresholds for SRML-2 (0.26), fair/poor SRH (0.29), and RLSM (0.32) were significantly higher than those for SRML-1 (0.18). ROC-based FI cutoffs were significantly lower than IRT-based values for SRML-2, SRH, and RLSM (0.12 to 0.17), and they varied minimally and non-systematically across the anchors. Conclusions: The IRT method identifies biologically plausible FI thresholds that could meaningfully complement and contextualize existing thresholds for defining frailty.
KW - Frailty
KW - Item response theory
KW - Receiver operating characteristic analysis
UR - http://www.scopus.com/inward/record.url?scp=85177858534&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.archger.2023.105280
DO - https://doi.org/10.1016/j.archger.2023.105280
M3 - Article
C2 - 38000095
SN - 0167-4943
VL - 117
JO - Archives of gerontology and geriatrics
JF - Archives of gerontology and geriatrics
M1 - 105280
ER -