The bioelectrical impedance phase angle as an indicator of undernutrition and adverse clinical outcome in cardiac surgical patients.
OBJECTIVE
In cardiac surgical patients, undernutrition increases the risk of adverse clinical outcome. We investigated whether the bioelectrical impedance phase angle is an indicator of undernutrition and clinical outcome in cardiac surgery.


METHODS
In 325 cardiac surgical patients, we prospectively analyzed the associations between a preoperative low phase angle, measured by bioelectrical impedance spectroscopy, and well-established indicators of undernutrition such as body mass index (kg/m(2)), unintended weight loss, and fat free mass index (kg/m(2)), and muscle strength (handgrip strength (kg)), immune function (C-reactive protein and albumin), and adverse clinical outcomes.


RESULTS
A low phase angle (<5.38°) was present in 29.8% (n = 96) of the patients, and was associated with low body mass index (p < 0.001), low fat free mass index (p < 0.001), and less handgrip strength (p = 0.063), but not with unintended weight loss or immune function. Furthermore, a preoperative low phase angle was associated with a prolonged intensive care unit and hospital stay (adj. hazard ratio: 0.68; 95%CI: 0.49-0.94; p = 0.020 and adj. hazard ratio: 0.74; 95%CI: 0.55-0.99; p = 0.048, respectively).


CONCLUSIONS
A preoperative low bioelectrical impedance phase angle is associated with undernutrition, and increases the risk of adverse clinical outcome after cardiac surgery. The phase angle might help to identify undernourished cardiac surgical patients.
Department of Cardiothoracic Surgery, Academic Medical Center University of Amsterdam, The Netherlands.
Marlieke
M
Visser
Lenny M W
LM
van Venrooij
Dominique C M
DC
Wanders
Rien
R
de Vos
Willem
W
Wisselink
Paul A M
PA
van Leeuwen
Bas A J M
BA
de Mol
D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis / Q000378:metabolism; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D017097:Electric Impedance; D005260:Female; D006760:Hospitalization; D006801:Humans; D007902:Length of Stay; D008297:Male; D044342:Malnutrition / Q000175:diagnosis* / Q000503:physiopathology; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D009752:Nutritional Status; D011300:Preoperative Care; D011446:Prospective Studies; D012709:Serum Albumin / Q000032:analysis; D016896:Treatment Outcome; D015431:Weight Loss
D012709:Serum Albumin; D002097:C-Reactive Protein