title: Phase angle, frailty and mortality in older adults.
abstract: BACKGROUND
  Frailty is a multidimensional phenotype that describes declining physical function and a vulnerability to adverse outcomes in the setting of physical stress such as illness or hospitalization. Phase angle is a composite measure of tissue resistance and reactance measured via bioelectrical impedance analysis (BIA). Whether phase angle is associated with frailty and mortality in the general population is unknown.
  
  
  OBJECTIVE
  To evaluate associations among phase angle, frailty and mortality.
  
  
  METHODS
  Population-based survey.
  
  
  METHODS
  Third National Health and Nutritional Examination Survey (1988-1994).
  
  
  METHODS
  In all, 4,667 persons aged 60 and older.
  
  
  METHODS
  Frailty was defined according to a set of criteria derived from a definition previously described and validated.
  
  
  RESULTS
  Narrow phase angle (the lowest quintile) was associated with a four-fold higher odds of frailty among women and a three-fold higher odds of frailty among men, adjusted for age, sex, race-ethnicity and comorbidity. Over a 12-year follow-up period, the adjusted relative hazard for mortality associated with narrow phase angle was 2.4 (95 % confidence interval [95 % CI] 1.8 to 3.1) in women and 2.2 (95 % CI 1.7 to 2.9) in men. Narrow phase angle was significantly associated with mortality even among participants with little or no comorbidity.
  
  
  CONCLUSIONS
  Analyses of BIA and frailty were cross-sectional; BIA was not measured serially and incident frailty during follow-up was not assessed. Participants examined at home were excluded from analysis because they did not undergo BIA.
  
  
  CONCLUSIONS
  Narrow phase angle is associated with frailty and mortality independent of age and comorbidity.
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Palo Alto, CA, USA, ewilhelm@stanford.edu.
authors.forename: Emilee R
authors.initials: ER
authors.lastname: Wilhelm-Leen
authors.forename: Yoshio N
authors.initials: YN
authors.lastname: Hall
authors.forename: Ralph I
authors.initials: RI
authors.lastname: Horwitz
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Chertow
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D001823:Body Composition / Q000502:physiology*; D015897:Comorbidity; D017097:Electric Impedance; D005260:Female; D016330:Frail Elderly / Q000706:statistics & numerical data*; D015577:Geriatric Assessment / Q000379:methods; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D012737:Sex Factors; D014481:United States / Q000453:epidemiology