Association Between the Phase Angle and Function Recovery in Patients With Hip Fractures

Patients with hip fractures frequently present with malnutrition, and proper nutritional management is recognized as an important factor in their clinical care.

We aimed to clarify whether the preoperative phase angle could predict postoperative functional recovery and to identify the impact of undernutrition on clinical outcomes in patients with hip fractures.

For 100 hip fracture patients, serum albumin level and muscle mass on the admission day were recorded. Muscle mass was estimated using plain computed tomography (CT) images with the skeletal muscle index (SMI). All participants were subjected to bioelectrical impedance analysis (BIA), and the phase angle was calculated at admission. Functional Independence Measure (FIM) scores on admission and at two weeks postoperatively and ΔFIM (the difference between the FIM score on admission and the score at two weeks postoperatively) were determined. Correlations among the phase angle, serum albumin level, SMI, and FIM scores were assessed.

Positive correlations were observed between the phase angle with both serum albumin level at admission (R=0.53, p<0.001) and SMI (R=0.43, p<0.001). Serum albumin level at admission and the phase angle were positively correlated with both the FIM score at two weeks postoperatively and ΔFIM. From multiple regression analysis with the FIM score at two weeks postoperatively or ΔFIM as the dependent variable, and the phase angle, serum albumin level at admission, and SMI as three independent variables, only the phase angle showed significant correlations with the FIM score at two weeks postoperatively (p<0.001) and ΔFIM (p<0.05).

The preoperative phase angle could predict postoperative functional recovery and identify the impact of undernutrition and sarcopenia on clinical outcomes in patients with hip fractures.