Comparison of the de Morton Mobility Index and Hierarchical Assessment of Balance and Mobility in older acute medical patients

OBJECTIVE: To compare the measurement properties of the de Morton Mobility Index (DEMMI) and the Hierarchical Assessment of Balance and Mobility (HABAM) in an older acute medical inpatient population. DESIGN: Cross-sectional. SUBJECTS: Older acute medical inpatients. METHODS: The DEMMI, HABAM and further assessments were performed after hospital admission. Construct validity was assessed by testing 13 hypotheses on convergent and known-groups validity. Test-retest reliability and minimal detectable change were estimated based on a re-assessment of unchanged patients. Floor and ceiling effects were used to indicate adequacy of scale width. RESULTS: For both the DEMMI and HABAM, 11 (85%) hypotheses regarding construct validity were confirmed (n = 158). Both scales showed strong correlations with other multi-component mobility scales (Spearman's rho 0.75-0.92). Neither floor nor ceiling effects were evident. The intraclass correlation coefficient was 0.98 (95% confidence interval (95% CI) 0.96-0.99) for the DEMMI and 0.99 (95% CI 0.99-0.99) for the HABAM, respectively (n = 30). The minimal detectable change with 90% confidence was 6 points on the 100-point DEMMI scale and 1 point on the 26-point HABAM scale. CONCLUSION: The DEMMI and the HABAM appear to be suitable for measuring mobility in older acute medical patients.