title: A single weekly Kt/Vurea target for peritoneal dialysis patients does not provide an equal dialysis dose for all.
abstract: Dialysis adequacy is traditionally based on urea clearance, adjusted for total body volume (Kt/Vurea), and clinical guidelines recommend a Kt/Vurea target for peritoneal dialysis. We wished to determine whether adjusting dialysis dose by resting and total energy expenditure would alter the delivered dialysis dose. The resting and total energy expenditures were determined by equations based on doubly labeled isotopic water studies and adjusted Kturea for resting energy expenditure and total energy expenditure in 148 peritoneal dialysis patients (mean age, 60.6 years; 97 male [65.5%]; 54 diabetic [36.5%]). The mean resting energy expenditure was 1534 kcal/d, and the total energy expenditure was 1974 kcal/day. Using a weekly target Kt/V of 1.7, Kt was calculated using V measured by bioimpedance and the significantly associated (r = 0.67) Watson equation for total body water. Adjusting Kt for resting energy expenditure showed a reduced delivered dialysis dose (ml/kcal per day) for women versus men (5.5 vs. 6.2), age under versus over 65 years (5.6 vs. 6.4), weight <65 versus >80 kg (5.8 vs. 6.1), low versus high comorbidity (5.9 vs. 6.2), all of which were significant. Adjusting for the total energy expenditure showed significantly reduced dosing for those employed versus not employed (4.3 vs. 4.8), a low versus high frailty score (4.5 vs. 5.0) and nondiabetic versus diabetic (4.6 vs. 4.9). Thus, the current paradigm for a single target Kt/Vurea for all peritoneal dialysis patients does not take into account energy expenditure and metabolic rate and may lead to lowered dialysis delivery for the younger, more active female patient.
authors.affiliation: UCL Centre for Nephrology, Royal Free Hospital, University College London Medical School, London, United Kingdom.
authors.forename: Sally
authors.initials: S
authors.lastname: El-Kateb
authors.affiliation: Renal Unit, Lister Hospital, Stevenage SG1 4AB, United Kingdom.
authors.forename: Sivakumar
authors.initials: S
authors.lastname: Sridharan
authors.affiliation: Renal Unit, Lister Hospital, Stevenage SG1 4AB, United Kingdom; University of Hertfordshire, Hatfield, United Kingdom.
authors.forename: Ken
authors.initials: K
authors.lastname: Farrington
authors.affiliation: Barts Health NHS Trust, London, United Kingdom.
authors.forename: Stanley
authors.initials: S
authors.lastname: Fan
authors.affiliation: UCL Centre for Nephrology, Royal Free Hospital, University College London Medical School, London, United Kingdom. Electronic address: andrewdavenport@nhs.net.
authors.forename: Andrew
authors.initials: A
authors.lastname: Davenport
mesh_terms: D000328:Adult; D000368:Aged; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000706:statistics & numerical data*
keywords: Kt/Vurea; body surface area; peritoneal dialysis; resting energy expenditure; total body water; total energy expenditure