Evaluating the accuracy of minimum data set bed-mobility ratings against independent performance assessments: Systematic error and directions for improvement

Purpose: The Minimum Data Set (MDS) Activities of Daily Living (ADL) bed-mobility item, which rates the staff-assistance level necessary for bed movement, is used to target scheduled repositioning interventions and to identify physical function changes in nursing home residents; however, accuracy of the item is uncertain. The purpose of this study was to evaluate the accuracy of the MDS ADL bed-mobility item as completed by nursing home nurses with independent performance assessments conducted by research staff. Design and Methods: A convenience sample of 197 long-stay residents from 26 California nursing homes participating in a larger project was used in this cross-sectional study to compare independent research-staff performance assessments (using graduated assistance protocols of residents' ability to move in bed) and nursing home nurse MDS bed-mobility ratings. Participants also wore movement monitors to verify performance assessments. Results: Poor agreement existed between the nursing home nurse MDS bed-mobility ratings and the research-staff performance assessments across all assistance levels (kappa range, kappa = 0.007, p = .918 to kappa = 0.484, p < .001), with better agreement seen in totally dependent participants and with fewer elapsed days between MDS ratings and performance assessments. The odds of nursing home nurse errors (underestimating or overestimating dependency) on the MDS bed-mobility item were 2.1 times higher for participants judged independent by research staff compared with participants judged as requiring physical assistance by research staff (95% confidence interval, 1.14-4.03) when adjusted for number of days between nurse MDS ratings and research-staff performance assessments. Implications: Nursing home nurses overestimated resident dependency in bed mobility. The systematic inaccuracies in MDS bed-mobility ratings have implications for their use as a basis for targeting residents for repositioning programs and determining changes in residents' physical function. Performance assessments utilizing graduated assistance protocols are recommended as a method of improving the accuracy of MDS bed-mobility ratings.