title: Hydration in advanced cancer: can bioelectrical impedance analysis improve the evidence base? A systematic review of the literature.
abstract: BACKGROUND
  Decisions surrounding the administration of clinically assisted hydration to patients dying of cancer can be challenging because of the limited understanding of hydration in advanced cancer and a lack of evidence to guide health care professionals. Bioelectrical impedance analysis (BIA) has been used to assess hydration in various patient groupings, but evidence for its use in advanced cancer is limited.
  
  
  OBJECTIVE
  To critically appraise existing methods of hydration status assessment in advanced cancer and review the potential for BIA to assess hydration in advanced cancer.
  
  
  METHODS
  Searches were carried out in four electronic databases. A hand search of selected peer-reviewed journals and conference abstracts also was conducted. Studies reporting (de)hydration assessment (physical examination, biochemical measures, symptom assessment, and BIA) in patients with advanced cancer were included.
  
  
  RESULTS
  The results highlight how clinical examination and biochemical tests are standard methods of assessing hydration, but limitations exist with these methods in advanced cancer. Furthermore, there is disagreement over the evidence for some commonly associated symptoms with dehydration in cancer. Although there are limitations with using BIA alone to assess hydration in advanced cancer, analysis of BIA raw measurements through the method of bioelectrical impedance vector analysis may have a role in this population.
  
  
  CONCLUSIONS
  The benefits and burdens of providing clinically assisted hydration to patients dying of cancer are unclear. Bioelectrical impedance vector analysis shows promise as a hydration assessment tool but requires further study in advanced cancer. Innovative methodologies for research are required to add to the evidence base and ultimately improve the care for the dying.
authors.affiliation: Marie Curie Palliative Care Institute Liverpool, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom. amaranwosu@doctors.org.uk
authors.forename: Amara Callistus
authors.initials: AC
authors.lastname: Nwosu
authors.forename: Catriona R
authors.initials: CR
authors.lastname: Mayland
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Mason
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Khodabukus
authors.forename: Andrea
authors.initials: A
authors.lastname: Varro
authors.forename: John E
authors.initials: JE
authors.lastname: Ellershaw
mesh_terms: D002307:Cardiography, Impedance / Q000379:methods* / Q000706:statistics & numerical data; D015984:Causality; D015897:Comorbidity; D003681:Dehydration / Q000453:epidemiology* / Q000451:nursing*; D019317:Evidence-Based Medicine; D005440:Fluid Therapy / Q000706:statistics & numerical data*; D006801:Humans; D009369:Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000451:nursing*; D017063:Outcome Assessment, Health Care / Q000379:methods* / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome