title: Estimation of protein requirements according to nitrogen balance for older hospitalized adults with pressure ulcers according to wound severity in Japan.
abstract: OBJECTIVE
  To estimate protein requirements in older hospitalized adults with pressure ulcers (PrU) according to systemic conditions and wound severity.
  
  
  METHODS
  Secondary nitrogen balance study over 3 days.
  
  
  METHODS
  Long-term care facility.
  
  
  METHODS
  Twenty-eight older adults with PrU using a urinary catheter.
  
  
  METHODS
  Nitrogen balance over 3 days was evaluated from habitual nitrogen intake measured using a food weighing record and nitrogen excretion from urine, feces and wound exudate. Nitrogen intake required to maintain nitrogen equilibrium was estimated as an average protein requirement using a linear mixed model.
  
  
  RESULTS
  Nitrogen intake at nitrogen equilibrium was 0.151 gN/kg per day (95% confidence interval = 0.127-0.175 gN/kg per day) for all participants. The amount of protein loss from wound exudate contributed little to total nitrogen excretion. A Charlson comorbidity index of 4 or greater (the median value) was related to lower nitrogen intake at nitrogen equilibrium (P = .005). Severe PrU with heavy exudate amounts and measured wound areas of 7.9 cm(2) or greater (the median value) were related to higher nitrogen intake at nitrogen equilibrium in individuals with a Charlson comorbidity index of 3 or less (both P = .04). Larger wound area (correlation coefficient (r) = 0.55, P = .003) and heavier exudate volume (r = 0.53, P = .004) were associated with muscle protein hypercatabolism measured according to 3-methylhistidine/creatinine ratio.
  
  
  CONCLUSIONS
  The average protein requirement is 0.95 g/kg per day for older hospitalized Japanese adults with PrU, but protein requirements depend on an individual's condition and wound severity and range from 0.75 to 1.30 g/kg per day. Severe PrU can require higher protein intakes because of muscle protein hypercatabolism rather than direct loss of protein from wound exudate.
authors.affiliation: Department of Gerontological Nursing and Wound Care Management, Division of Health Sciences and Nursing, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. iizaka-tky@umin.ac.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Iizaka
authors.forename: Junko
authors.initials: J
authors.lastname: Matsuo
authors.forename: Chizuko
authors.initials: C
authors.lastname: Konya
authors.forename: Rie
authors.initials: R
authors.lastname: Sekine
authors.forename: Junko
authors.initials: J
authors.lastname: Sugama
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sanada
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004044:Dietary Proteins; D005260:Female; D006760:Hospitalization; D006801:Humans; D007564:Japan; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D009751:Nutritional Requirements; D003668:Pressure Ulcer / Q000378:metabolism*; D012720:Severity of Illness Index
chemical_list: D004044:Dietary Proteins; D009584:Nitrogen