Association Between Multi-frequency Phase Angle and Survival in Patients With Advanced Cancer

Abstract

Context: The ability to predict survival accurately has implications in clinical decision making.

Objectives: We determined the association of phase angle obtained from multi-frequency bioelectric impedance analysis with overall survival in patients with advanced cancer.

Methods: We included consecutive patients with advanced cancer who had an outpatient palliative care consultation. Multi-frequency bioelectric impedance analysis assessed phase angle at three different frequencies (5/50/250 kHz) on each hemibody (right/left). Survival analysis was conducted using the Kaplan-Meier method, log-rank test, and multivariate Cox regression analysis.

Results: Among 366 patients, the median overall survival was 250 days (95% confidence interval 191-303 days). The mean phase angle for 5, 50, and 250 kHz were 2.2°, 4.4°, and 4.2° on the right and 2.0°, 4.2° and 4.1° on the left, respectively. For all six phase angles, a lower value was significantly associated with a poorer overall survival (P < 0.001). After adjusting for cancer type, performance status, weight loss, and inflammatory markers, phase angle remained independently associated with overall survival (hazard ratio 0.85 per degree increase, 95% confidence interval 0.72-0.99; P = 0.048).

Conclusion: Phase angle represents a novel objective prognostic factor in outpatient palliative cancer care setting, regardless of frequency and body sides.

Keywords: Electric impedance; forecasting; neoplasms; palliative care; prognosis; survival.