Minimal Important Change in the Berg Balance Scale in Older Women with Vertebral Compression Fractures: A Retrospective Multicenter Study.

BackgroundVertebral compression fractures, which are commonly associated with older age and osteoporotic fractures, have an increased risk of re-fracture. Therefore, improving balance is important to prevent falls. The minimal important change (MIC) has been recommended for interpreting clinically meaningful changes in rating scales. The MIC of the Berg Balance Scale (BBS) for use in older women with vertebral compression fractures has not been established.ObjectiveTo identify the MIC of the BBS that can be used in older women with vertebral compression fractures using predictive modeling methods and the receiver-operating characteristic (ROC)-based method.DesignA retrospective longitudinal multicenter study.PatientsSixty older women (mean age +/- standard deviation: 84.1 +/- 7.0 years) with vertebral compression fractures who were unable to ambulate independently on a level surface.MethodsA change of one point in the Functional Ambulation Category (FAC) was used as an anchor to calculate the MIC of the BBS based on the change between admission and discharge. We calculated the MIC for the women whose FAC score improved by >= 1 point. We used three anchor-based methods to examine the MIC: the ROC-based method (MICROC), the predictive modeling method (MICpred), and the MICpred-based method adjusted by the rate of improvement and reliability of transition (MICadj).ResultsThirty-nine women comprised the "important change" group based on their FAC score improvement. In this group, the MICROC (95% confidence interval [CI]) value of the BBS was 10.0 points (5.5-15.5), with an area under the curve of 0.71. The MICpred (95% CI) value was 9.7 (8.1-11.0), and the MICadj (95% CI) was 7.0 (5.5-8.5) points.ConclusionFor women with vertebral compression fractures who are unable to ambulate independently, a 7.0-point improvement in the BBS score may be a useful indicator for reducing the amount of assistance required for walking.