Phase angle as a prognostic indicator of surgical outcomes in patients with gastrointestinal cancer

Background: In patients with gastrointestinal cancer with planned elective surgery, malnutrition increases the risk of adverse outcomes in the postoperative period. The phase angle, measured by the bioelectrical impedance analysis is an indicator of the metabolic and functional status of the patient. It may be an important prognostic indicator for the clinical outcome of post-surgical treatment in patients with gastrointestinal cancer.

Patients and methods: In this prospective study, 70 patients with gastrointestinal cancer had their phase angles measured by the bioelectrical impedance analysis before the surgery. During the first month after the surgery, we documented the postoperative complications from the patient's records and classified them according to the Clavien Dindo classification of surgical complications. The time of hospitalization was also recorded. The data was statistically analysed in SPSS.

Results: We found a statistically significant difference (p = 0.036) in the average value of phase angles between the group of patients who had postoperative complications (phase angle 5.09°) and the group without postoperative complications (5.64°). We noted a correlating trend of decreasing phase angle values and increasing hospitalization time (Pe R = -0,40, p = 0,001). The phase angle cut-off value (5.5°) was calculated using the ROC curve method, predicting a higher risk of the postoperative complications (p = 0,037) in patients with lower phase angle.

Conclusions: Lower phase angle values before surgery were associated with more complications during the first month after surgery and longer hospitalization time. We found that a phase angle below than 5.5° could serve as a marker that predicts a greater risk of postoperative complications.