Bioelectrical Impedance Phase Angle as a Predictors of Mortality in Patients with Lung Cancer: a Prospective Study

Objective Bioelectrical impedance analysis (BIA) is used to measure a patient's body composition. The phase angle (PA), the major parameter in BIA, is one of the most sensitive indicators of malnutrition. The aim of the current study was to investigate whether the PA can be used to predict survival in lung cancer patients. Methods One hundred sixty-six lung cancer patients were prospectively included from January 2014 to August 2016 in Daping Hospital. Anthropometric measurements, hematological values, the nutritional risk screening (NRS 2002) score, patient generated-subjective global assessment (PG-SGA) score, Karnofsky performance status (KPS) scale, European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ C-30) score, and BIA were investigated within 48 hours after admission to the hospital. A Spearman correlation analysis was applied to test the correlations between the study characteristics and PA. A Kaplan-Meier analysis and log-rank test were conducted to analyze the association between the overall survival (OS) and PA. Results The mean age for all patients was 63 years old (42 females and 124 males). The median PA was 5.5°(4.70°, 6.23°). The PA was positively associated with the body mass index, hand grip strength, mid-arm circumference, mid-arm muscle circumference, albumin, prealbumin, C-reactive protein, red blood cells, hemoglobin and KPS score. The PG-SGA scores, QLQ-C30 score, and NRS2002 score showed a significant negative association with the PA. According to a multivariate analysis, the PA (HR = 0.47; 95％ CI: 0.27-0.81) was independent predictor of the lung cancer patients' long-term OS. Patients with a higher PA (≥ 5°) had better overall survival (median = 426 days) compared to those with a lower PA (< 5°) (median = 96 days) based on the one-year follow-up data (P < 0.0001). Conclusions These studies indicate that the PA is a sensitive and early indicator to predict survival in lung cancer patients.