Impact of phase angle on postoperative prognosis in patients with gastrointestinal and hepatobiliary-pancreatic cancer

Phase angle (PhA), by bioelectrical impedance analysis, has been used in patients with several diseases; however, its prognostic value in patients with gastrointestinal (GI) and hepatobiliary-pancreatic (HBP) cancer is unclear. The aim of the present study was to investigate the effects of PhA on postoperative short- outcomes and long-term survival in these patients. This retrospective study reviewed data from 501 patients with GI and HBP cancers who underwent first resection surgery. The data were divided into the following groups according to the preoperative PhA quartile values by sex: high-PhA group with the highest quartile (Q4), normal-PhA group with middle quartiles (Q3 and Q2), and low-PhA group with the lowest quartile (Q1). Preoperative nutritional statuses, postoperative short-term outcomes during hospitalization, and 5-y survival between three groups were compared. Cox proportional hazard models were used to evaluate the prognostic effect of PhA. PhA positively correlated with body weight, skeletal muscle mass, and handgrip strength, and negatively correlated with age and levels of C-reactive protein. The low-PhA group showed a higher prevalence of malnutrition (48%) than normal-PhA (25%), and high-PhA groups (9%; P < 0.001). The incidence of postoperative severe complications was 10% for all patients (14% in low-PhA, 12% in normal-PhA, and 4% in high-PhA; P = 0.018). The incidence of prolonged stays in a postoperative high-care or intensive care unit was 8% in all patients (16% in low-PhA, 8% in normal-PhA, and 2% in high-PhA; P < 0.001). The 5-y survival rate was 74% in all patients (68% in low-PhA, 74% in normal-PhA, and 79% in high-PhA; P < 0.001). The multivariate analysis demonstrated that a low-PhA group was an independent risk factor for mortality (hazard ratio, 1.99; 95% confidence interval, 1.05–3.90; P = 0.034). PhA is a useful short-term and long-term postoperative prognostic marker for patients with GI and HBP cancers. •We analyzed patients with gastrointestinal and hepatobiliary–pancreatic cancer.•Low phase angle (PhA) had high levels of malnutrition, sarcopenia, and cachexia.•Low PhA was an independent risk factor for longer postoperative critical care.•Low PhA was an independent risk factor for long-term poor survival.•PhA is a useful short- and long-term prognostic marker for these patients.