Scaling Hemodialysis Target Dose to Reflect Body Surface Area, Metabolic Activity, and Protein Catabolic Rate: A Prospective, Cross-sectional Study.
BACKGROUND
Women and small men treated by hemodialysis (HD) have reduced survival. This may be due to use of total-body water (V) as the normalizing factor for dialysis dosing. In this study, we explored the equivalent dialysis dose that would be delivered using alternative scaling parameters matching the current recommended minimum Kt/V target of 1.2.


METHODS
Prospective cross-sectional study.


METHODS
1,500 HD patients on a thrice-weekly schedule, recruited across 5 different centers.


METHODS
Age, sex, weight, race/ethnicity, comorbid condition level, and employment status.


RESULTS
Kt was estimated by multiplying V by 1.2. Kt/body surface area (BSA), Kt/resting energy expenditure (REE), Kt/total energy expenditure (TEE) and Kt/normalized protein catabolic rate (nPCR) equivalent to a target Kt/V of 1.2 were then estimated by dividing Kt by the respective parameters.


METHODS
Anthropometry, HD adequacy details, and BSA were obtained by standard procedures. REE was estimated using a novel validated equation. TEE was calculated from physical activity data obtained using the Recent Physical Activity Questionnaire. nPCR was estimated using a standard formula.


RESULTS
Mean BSA was 1.87m2; mean REE, 1,545kcal/d; mean TEE, 1,841kcal/d; and mean nPCR, 1.03g/kg/d. For Kt/V of 1.2, there was a wide range of equivalent doses expressed as Kt/BSA, Kt/REE, Kt/TEE, and Kt/nPCR. The mean equivalent dose was lower in women for all 4 parameters (P<0.001). Small men would also receive lower doses compared with larger men. Younger patients, those with low comorbidity, those employed, and those of South Asian race/ethnicity would receive significantly lower dialysis doses with current practice.


CONCLUSIONS
Cross-sectional study; physical activity data collected by an activity questionnaire.


CONCLUSIONS
Current dosing practices may risk underdialysis in women, men of smaller body size, and specific subgroups of patients. Using BSA-, REE-, or TEE-based dialysis prescription would result in higher dose delivery in these patients.
Renal Unit, Lister Hospital, Stevenage, United Kingdom. Electronic address: sridharansivakumar@gmail.com.
Sivakumar
S
Sridharan
Renal Unit, Lister Hospital, Stevenage, United Kingdom; University of Hertfordshire, Hatfield, United Kingdom.
Enric
E
Vilar
Royal Free Hospital, London, United Kingdom.
Andrew
A
Davenport
Royal London Hospital, London, United Kingdom.
Neil
N
Ashman
Southend University Hospital, Westcliff-on-Sea, United Kingdom.
Michael
M
Almond
Arrowe Park Hospital, Wirral, United Kingdom.
Anindya
A
Banerjee
Anglia Ruskin University, Cambridge, United Kingdom.
Justin
J
Roberts
Renal Unit, Lister Hospital, Stevenage, United Kingdom; University of Hertfordshire, Hatfield, United Kingdom.
Ken
K
Farrington
D001830:Body Surface Area; D003430:Cross-Sectional Studies; D004734:Energy Metabolism; D005260:Female; D015312:Hemodialysis Solutions / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011506:Proteins / Q000378:metabolism*; D006435:Renal Dialysis / Q000379:methods*
D015312:Hemodialysis Solutions; D011506:Proteins
Hemodialysis target dose; Kt/V; body size; dialysis adequacy; dialysis dosing; end-stage renal disease (ESRD); energy expenditure; metabolism; physical activity; sex differences