title: The relationship between bioelectrical impedance phase angle and subjective global assessment in advanced colorectal cancer.
abstract: BACKGROUND
  Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer.
  
  
  METHODS
  We evaluated a case series of 73 stages III and IV colorectal cancer patients. Patients were classified as either well-nourished or malnourished using the SGA. BIA was conducted on all patients and phase angle was calculated. The correlation between phase angle and SGA was studied using Spearman correlation coefficient. Receiver Operating Characteristic curves were estimated using the non-parametric method to determine the optimal cut-off levels of phase angle.
  
  
  RESULTS
  Well-nourished patients had a statistically significantly higher (p = 0.005) median phase angle score (6.12) as compared to those who were malnourished (5.18). The Spearman rank correlation coefficient between phase angle and SGA was found to be 0.33 (p = 0.004), suggesting better nutritional status with higher phase angle scores. A phase angle cut-off of 5.2 was 51.7% sensitive and 79.5% specific whereas a cut-off of 6.0 was 82.8% sensitive and 54.5% specific in detecting malnutrition. Interestingly, a phase angle cut-off of 5.9 demonstrated high diagnostic accuracy in males who had failed primary treatment for advanced colorectal cancer.
  
  
  CONCLUSIONS
  Our study suggests that bioimpedance phase angle is a potential nutritional indicator in advanced colorectal cancer. Further research is needed to elucidate the optimal cut-off levels of phase angle that can be incorporated into the oncology clinic for better nutritional evaluation and management.
authors.affiliation: Cancer Treatment Centers of America at Midwestern Regional Medical Center, 2610 Sheridan Road, Zion, IL 60099, USA. gupta_digant@yahoo.com
authors.forename: Digant
authors.initials: D
authors.lastname: Gupta
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Lis
authors.forename: Sadie L
authors.initials: SL
authors.lastname: Dahlk
authors.forename: Jessica
authors.initials: J
authors.lastname: King
authors.forename: Pankaj G
authors.initials: PG
authors.lastname: Vashi
authors.forename: James F
authors.initials: JF
authors.lastname: Grutsch
authors.forename: Carolyn A
authors.initials: CA
authors.lastname: Lammersfeld
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000150:complications*; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D044342:Malnutrition / Q000175:diagnosis* / Q000209:etiology; D008875:Middle Aged; D009367:Neoplasm Staging; D015596:Nutrition Assessment; D009752:Nutritional Status; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric