Bioelectrical phase angle predicts quality of life and mortality with cancer
Bioelectrical phase angle, which we easily and non-invasively measure in the clinic by bioelectrical impedance analysis, has been validated by numerous studies as a prognostic indicator for a variety of medical conditions. A study recently published in The American Journal of Clinical Nutrition offers evidence for its accuracy in predicting life quality, nutritional status and mortality for patients with cancer. The authors state:
"The bioelectrical phase angle has shown predictive potential in various diseases...This study evaluated the prognostic value of the fifth percentile of sex-, age-, and body mass index–stratified phase angle reference values in patients with cancer with respect to nutritional and functional status, quality of life, and 6-mo mortality."
They then examined how the standardized phase angle and its deviation from population averages ('z score') on these life and mortality variables. They tested phase angle with bioelectical impedance analysis, muscle strength by handgrip and peak expiratory flow, employed assessments for quality of life and nutritional status, and documented survival after 6 months for 399 patients. What did the data show?
"Patients with a phase angle of less than the fifth reference percentile had significantly lower nutritional and functional status, impaired quality of life, and increased mortality. The standardized phase angle emerged as a significant predictor for malnutrition and impaired functional status in generalized linear model regression analyses. It was also a stronger indicator of 6-mo survival than were malnutrition and disease severity in the Cox regression model..."
Having an accurate, easy and inexpensive instrument to objectively evaluate the effectiveness of therapeutic case management in cancer in respect to mortality, function, quality of life and nutritional status is a resource that should not be overlooked by clinicians. The authors conclude:
"The standardized phase angle is an independent predictor for impaired nutritional and functional status and survival. The fifth phase angle reference percentile is a simple and prognostically relevant cutoff for detection of patients with cancer at risk for these factors."
Note: This refers to bioelectrical impedance analysis measured by a professional clinical-grade instrument.