title: Bioelectrical impedance analysis is more accurate than clinical examination in determining the volaemic status of elderly patients with fragility fracture and hyponatraemia.
abstract: OBJECTIVE
  Management of hyponatraemia depends crucially on accurate determination of volaemic (hydration) status but this is notoriously challenging to measure in older people. Bioelectrical impedance analysis (BIA) provides a validated means of determining total body water (TBW), but its clinical utility in determining volaemic status in hyponatraemia has never been tested. This study assessed the utility of BIA in the clinical management of hyponatraemia in elderly patients with fragility fractures (EPFF), a group at high risk of hyponatraemia.
  
  
  METHODS
  Prospective observational study of consenting patients ≥65 years with fragility fractures (N=127).
  
  
  METHODS
  University teaching hospital in Scotland.
  
  
  METHODS
  Patients ≥665 years with fragility fractures with capacity to consent to participation.
  
  
  METHODS
  BIA and standard clinical examination procedures (jugular venous distension, skin turgor, mouth and axillary moistness, peripheral oedema, capillary refill time, overall impression) were performed daily throughout each participant's hospital stay. Volaemic status of hyponatraemia was determined by an expert panel using clinical data (history, examination, nursing observations and laboratory tests) blinded to TBW readings. Cohen's kappa was calculated to assess the level of agreement between the expert panel and both BIA and standard clinical examination measures in determining the volaemic state of hyponatraemia.
  
  
  RESULTS
  26/33 (79%) cases of hyponatraemia had sufficient clinical information to allow determination of volaemic status by BIA. There was moderate level of agreement between BIA and the expert panel, kappa 0.52 (p<.001). All kappa values for standard clinical assessments of volaemic status neared zero, indicating nil to slight agreement.
  
  
  CONCLUSIONS
  BIA outperformed all aspects of the standard clinical examination in determining the volaemic status of hyponatraemic EPFF, suggesting it may be useful in clinical practice.
authors.affiliation: Dr Roy L Soiza, c/o Wards 11/12, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, AB25 2ZN, tel: 00 44 1224 558109; e-mail: roy.soiza@nhs.net.
authors.forename: K
authors.initials: K
authors.lastname: Cumming
authors.forename: G E
authors.initials: GE
authors.lastname: Hoyle
authors.forename: J D
authors.initials: JD
authors.lastname: Hutchison
authors.forename: R L
authors.initials: RL
authors.lastname: Soiza
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001834:Body Water; D017097:Electric Impedance; D005260:Female; D050723:Fractures, Bone / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D007010:Hyponatremia / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D010024:Osteoporosis / Q000150:complications / Q000503:physiopathology; D010808:Physical Examination; D010953:Plasma Volume; D011446:Prospective Studies; D015203:Reproducibility of Results; D012606:Scotland