title: Short-term body weight fluctuations in older well-hydrated hospitalised patients.
abstract: BACKGROUND
  The usual daily weight fluctuations of well-hydrated older hospitalised people have not been documented internationally. To date, dehydration assessments based on a short-term body weight change defined as >2% have been drawn from healthy population data. The present pilot study aimed to describe usual body weight fluctuation at the same time of day over a 3-day time frame in well-hydrated older hospitalised adults.
  
  
  METHODS
  An observational study of non-acute inpatients (n = 10) admitted to a Geriatric and Rehabilitation Unit, aged ≥60 years, assessed as well-hydrated, mobile, non-amputee and without conditions that influenced fluid status, was conducted. Participants were weighed hourly over a 9-h period for 3 days. Food and fluid intake, clothing items added or removed, and urine and faecal output were recorded.
  
  
  RESULTS
  Weight fluctuation for each participant [mean (SD) 80.2 (4.2) years; male 60.0%, n = 10] over 3 days ranged from 1.1% to 3.6%. Over 3 days, 40.0% (4/10) of participants had weight fluctuations of >2% and 20% (2/10) had weight fluctuations of >3%. Time of weigh-in accounted for 99.8% of the variation in weight fluctuation (P < 0.05), with the lowest fluctuations observed when weights were compared at the same time each day (≤0.4 kg).
  
  
  CONCLUSIONS
  Weights recorded at the same time daily had the greatest accuracy. Given that the range 1.1-3.6% was within normal weight fluctuations for well-hydrated older hospitalised participants, the weight change indicative of dehydration remains to be established in this setting but appears greater than conventionally used figures.
authors.affiliation: Department of Nutrition and Dietetics, Princess Alexandra Hospital, Brisbane, QLD, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Vivanti
authors.forename: L
authors.initials: L
authors.lastname: Yu
authors.forename: M
authors.initials: M
authors.lastname: Palmer
authors.forename: L
authors.initials: L
authors.lastname: Dakin
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: K
authors.initials: K
authors.lastname: Campbell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001835:Body Weight; D003681:Dehydration / Q000378:metabolism*; D005243:Feces; D005260:Female; D006801:Humans; D007297:Inpatients / Q000706:statistics & numerical data*; D016014:Linear Models; D008297:Male; D015596:Nutrition Assessment; D012016:Reference Values
keywords: assessment; dehydration; elderly; hydration; older; weight