A systematic review of mobility instruments and their measurement properties for older acute medical patients

Background: Independent mobility is a key factor in determining readiness for discharge for older patients following acute hospitalisation and has also been identified as a predictor of many important outcomes for this patient group. This review aimed to identify a physical performance instrument that is not disease specific that has the properties required to accurately measure and monitor the mobility of older medical patients in the acute hospital setting. Methods: Databases initially searched were Medline, Cinahl, Embase, Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Trials without language restriction or limits on year of publication until July 2005. After analysis of this yield, a second step was the systematic search of Medline, Cinahl and Embase until August 2005 for evidence of the clinical utility of each potentially suitable instrument. Reports were included in this review if instruments described had face validity for measuring from bed bound to independent levels of ambulation, the items were suitable for application in an acute hospital setting and the instrument required observation (rather than self-report) of physical performance. Evidence of the clinical utility of each potentially suitable instrument was considered if data on measurement properties were reported. Results: Three instruments, the Elderly Mobility Scale (EMS), Hierarchical Assessment of Balance and Mobility (HABAM) and the Physical Performance Mobility Examination (PPME) were identified as potentially relevant. Clinimetric evaluation indicated that the HABAM has the most desirable properties of these three instruments. However, the HABAM has the limitation of a ceiling effect in an older acute medical patient population and reliability and minimally clinically important difference (MCID) estimates have not been reported for the Rasch refined HABAM. These limitations support the proposal that a new mobility instrument is required for older acute medical patients. Conclusion: No existing instrument has the properties required to accurately measure and monitor mobility of older acute medical patients.