Physical functioning is an important health domain for adults.
Evaluate physical functioning items in Medicare beneficiaries.
Survey data from the 2010 Consumer Assessment of Healthcare Providers and Systems Medicare survey.
The 366,701 respondents were 58% female; 38% were 75 or older; 57% had high school education or less.
Walking, getting in or out of chairs, bathing, dressing, toileting, and eating assessed with 3 response choices: unable to do, have difficulty, do not have difficulty.
Pearson correlations among the 6 items ranged from 0.515 to 0.835 (coefficient α=0.92). A single factor categorical factor analytic model fit the data well (comparative fit index=0.998; root mean square error of approximation=0.083). The item with the highest percentage of respondents reporting no difficulty was eating, followed by toileting, dressing, bathing, getting in and out of a chair, and walking. Threshold parameters from an item response theory–graded response model ranged from −1.983 (between unable to do and have difficulty eating) to −0.551 (between have difficulty and no difficulty walking). Item discrimination parameters ranged from 4.632 (walking) to 8.228 (dressing). IRT-scored physical functioning scores correlated with self-rated general health (r=0.389, n=344,843, P<0.0001) mental health (r=0.296, n=351,254, P<0.0001) and number of chronic conditions (r=−0.229, n=284,507, P<0.0001).
The physical functioning items target relatively easy activities, providing information for a minority of people in the sample with the lowest levels of physical functioning. Items representing higher levels of physical functioning are needed for the majority of the Medicare beneficiaries.
Supplemental Digital Content is available in the text.
*UCLA Department of Medicine, Los Angeles
†RAND Corporation, Santa Monica, CA
‡Centers for Medicare & Medicaid Services, Baltimore, MD
Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website, www.lww-medicalcare.com.
Supported by CMS contract HHSM-500-2005-000281 to RAND. R.D.H. was also supported in part by grants from AHRQ (2U18 HS016980), NIA (P30AG021684), NIMHD (2P20MD000182), and NCI (1U2-CCA186878-01).
The authors declare no conflict of interest.
Reprints: Ron D. Hays, PhD, UCLA Department of Medicine, 911 Broxton Avenue, Los Angeles, CA 90024. E-mail: email@example.com.