Is phase angle a valuable prognostic tool in cancer patients' survival? A systematic review and meta-analysis of available literature

Background & aims The phase angle (PA), expressed via bioelectrical impedance, is an indicator of cell membrane health and integrity, hydration, and nutritional status, and may have further application as a prognostic marker in cancer survival. However, the associations between PA and cancer survival are inconsistent and unclear. The present systematic review and meta-analysis investigated the relationship between PA and survival among adult patients diagnosed with cancer. Methods A systematic search of observational studies up to November 2020 was conducted through PubMed, Scopus, and ISI Web of Science. The critical appraisal of the eligible studies was performed using the Newcastle–Ottawa Quality Assessment Scale. Statistical analyses were performed using STATA 11.2 software. A P-value <0.05 was considered statistically significant. Results A total of 14 studies covering 2625 participants were included in this study. There was a positive and significant correlation between PA and cancer survival (Fisher's Z: 0.30; 95% CI, 0.21–0.40; P < 0.001; I2 = 0.0%). Also, there was a significant prognostic role for PA on patients' survival (HR 0.77; 95% CI, 0.74–0.81; P < 0.001; I2 = 0.0%). In other words, patients with low values of PA were 23% less likely to survive than patients with high values of PA. Conclusions Given that predicting survival in advanced cancer patients remains a challenge, the findings of this systematic review and meta-analysis suggest that phase angle may be an important prognostic factor of survival in this population.