@article{ajphr2020861,
author={Hart, Peter D.},
title={An IRT-constructed Brief Physical Functioning Scale and Its Association with Health Status},
journal={American Journal of Public Health Research},
volume={8},
number={6},
pages={184--189},
year={2020},
url={http://pubs.sciepub.com/ajphr/8/6/1},
issn={2327-6703},
abstract={<b>Background</b>: This study used item response theory (IRT) to create a brief PF scale (BPFS) and subsequently examined its relationship with several health characteristics. <b>Methods</b>: Data were used from <i>N</i>=1,716 adults 50+ years of age participating in a large health survey. A pool of 19 PF items were dichotomized to either 1 (any amount of difficulty) or 0 (no difficulty). A 2-parameter logistic (2PL) IRT model was used to evaluate item fit to the unidimensional PF construct. Criteria used to eliminate an item was 1) a small discrimination (slope) parameter, 2) a significant chi-square statistic for cell residuals, and 3) a large root mean square error of approximation (RMSEA). The IRT model was continually re-fitted until all remaining items met criteria. SAS PROC IRT and R ltm were used for scale construction. <b>Results</b>: The IRT analysis resulted in 8 well-fitting items with large item discrimination (<i>a</i>s > 2.03), moderate item difficulty range (<i>b</i>s: -0.07 - 1.35), and adequate item fit (RMSEAs &lt; .036). After full adjustment, each additional BPFS point significantly (<i>p</i>s &lt; .05) increased stepwise the odds of reporting poor HRQOL (<i>OR</i> = 1.59), being depressed (<i>OR</i> = 1.46), having thoughts of suicide (<i>OR</i> = 1.35), not meeting PA guidelines (<i>OR</i> = 1.29), being BMI-obese (<i>OR</i> = 1.23), being WC-obese (<i>OR</i> = 1.13), experiencing poor sleep (<i>OR</i> = 1.29), and reporting sleepiness (<i>OR</i> = 1.16). <b>Conclusion</b>: Results from this study show that the IRT-constructed BPFS is an efficient and valid tool that can predict health status in older adults.},
doi={10.12691/ajphr-8-6-1}
publisher={Science and Education Publishing}
}