Phase angle as a predictor of functional outcomes in patients undergoing in-hospital rehabilitation after hip fracture surgery

Abstract

Objectives: To evaluate the association between the phase angle and functional outcomes in patients after in-hospital postoperative rehabilitation for fragility hip fracture.

Methods: A prospective observational study was conducted in 68 patients over 65 years of age who had undergone a two-week postoperative rehabilitation for hip fracture. Phase angle of the non-fractured limb was used to reduce the error caused by postoperative edema. Participants were divided into groups according to phase angle terciles. Multivariable linear regression models adjusted for relevant factors known to affect functional outcomes after hip fracture were performed to identify the association between phase angle of the non-fractured limb and functional outcomes at discharge as evaluated the Functional Ambulation Category and Berg Balance Scale.

Results: The mean age of this study population was 81.9 ± 6.2 years and the average phase angle of the non-fractured limb was 3.6 ± 1.3°. The lowest tercile of phase angle (<3.0°) was independently associated with worse functional outcomes as measured by the Functional Ambulation Category and Berg Balance Scale at discharge (adjusted coefficient [β] = -0.287, P = 0.004; β = -0.172, P = 0.049, respectively) after adjusting for relevant covariates.

Conclusions: Low phase angle of the non-fractured limb was independently associated with worse functional outcomes at rehabilitation discharge in patients who undergoing hip fracture surgery. Phase angle may reflect both the pre-fracture body composition and functional status. It is a useful indicator for functional outcomes after postoperative rehabilitation for fragility hip fracture.