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.