title: Comparison of energy estimates in chronic kidney disease using doubly-labelled water.
abstract: BACKGROUND
  Total energy expenditure (TEE) is estimated in clinical practice as a combined measure of resting energy expenditure and physical activity level. Commonly available questionnaires to estimate physical activity level have not been validated in patients with kidney disease using the doubly-labelled water method.
  
  
  METHODS
  This prospective, cross-sectional study was conducted on 40 patients with chronic kidney disease stages 1-5 with the objective of validating two physical activity questionnaires: the Recent Physical Activity Questionnaire (RPAQ) and the Stanford 7-day recall questionnaire. TEE was measured using doubly-labelled water technique. TEE was also estimated using predicted resting energy expenditure and estimated physical activity measures from the questionnaires.
  
  
  RESULTS
  Measured TEE correlated better with TEE estimated from RPAQ compared to that from the Stanford questionnaire. In Bland-Altman analysis, TEE estimated from RPAQ had the least bias and narrower limits of agreement compared to the measured TEE. A metabolic equivalent of task value of 1.3 for the unaccounted time in RPAQ provided the best approximation of estimated TEE to the measured TEE.
  
  
  CONCLUSIONS
  RPAQ is an acceptable questionnaire tool for assessing physical activity level in patients with chronic kidney disease.
authors.affiliation: Renal Unit, Lister Hospital, Stevenage, UK.
authors.forename: S
authors.identifier: http://orcid.org/0000-0002-3390-9590
authors.initials: S
authors.lastname: Sridharan
authors.affiliation: Renal Unit, Lister Hospital, Stevenage, UK.
authors.forename: J
authors.initials: J
authors.lastname: Wong
authors.affiliation: Renal Unit, Lister Hospital, Stevenage, UK.|University of Hertfordshire, Hatfield, UK.
authors.forename: E
authors.initials: E
authors.lastname: Vilar
authors.affiliation: Renal Unit, Lister Hospital, Stevenage, UK.|University of Hertfordshire, Hatfield, UK.
authors.forename: K
authors.initials: K
authors.lastname: Farrington
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D001835:Body Weight; D003430:Cross-Sectional Studies; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000378:metabolism*; D011795:Surveys and Questionnaires; D014867:Water
chemical_list: D014867:Water
keywords: chronic kidney disease; doubly-labelled water; energy expenditure