Pediatric Nephrology

, Volume 28, Issue 5, pp 797–801 | Cite as

Two-point normalized protein catabolic rate overestimates nPCR in pediatric hemodialysis patients

  • Poyyapakkam R. Srivaths
  • Scott Sutherland
  • Steven Alexander
  • Stuart L. Goldstein
Original Article



Normalized protein catabolic rate (nPCR) calculation depends on estimating the urea generation between consecutive hemodialysis (HD) treatments. Two-point nPCR using blood urea nitrogen (BUN) before and after the same HD treatment has not been validated in pediatric patients, who typically receive a more intense HD dose than adults. This study aimed to compare nPCR calculated with a two-point vs. a three-point nPCR model in pediatric HD patients.


Pediatric patients receiving HD at 2 units were enrolled. Three BUN measurements were obtained around a midweek HD treatment: one prior to HD (preBUN1), one 30 s after HD (30sBUN), and one prior to the subsequent HD (preBUN2). The two-point nPCR model was calculated using preBUN1 and 30sBUN and the three-point nPCR model was calculated using preBUN2 and 30sBUN.


Seventy-six BUN sets from 35 patients were analyzed. Mean age was 16.4 ± 3.5 years. Mean dry weight was 51.4 ± 17.1 kg. Mean spKt/V was 1.54 ± 0.23. Mean preBUN2 was significantly lower than mean preBUN1 (60.2 ± 18.6 vs. 64.0 ± 18.9 mg/dl, p = 0.0001). nPCR obtained from the three-point model was significantly lower than nPCR obtained from the two-point model (1.07 ± 0.31 vs. 1.17 ± 0.31 g/kg/day, p = 0.00001). Seven of 76 (9.2 %) paired comparisons yielded three-point nPCR <1 vs. two-point nPCR >1.


Our data show that in pediatric patients receiving HD, the ((1) two-point and three-point models lead to significantly different nPCRs, and (2) inaccurate protein intake assessment may result from reliance on a two-point model for nPCR estimates.


Nutrition Chronic dialysis Children 


  1. 1.
    Kalantar-Zadeh K, Ikizler TA, Block G, Avram MM, Kopple JD (2003) Malnutrition-inflammation complex syndrome in dialysis patients: causes and consequences. Am J Kidney Dis 42:864–881PubMedCrossRefGoogle Scholar
  2. 2.
    Kopple JD (1999) Pathophysiology of protein-energy wasting in chronic renal failure. J Nutr 129:247S–251SPubMedGoogle Scholar
  3. 3.
    Stenvinkel P, Heimburger O, Paultre F, Diczfalusy U, Wang T, Berglund L, Jogestrand T (1999) Strong association between malnutrition, inflammation, and atherosclerosis in chronic renal failure. Kidney Int 55:1899–1911PubMedCrossRefGoogle Scholar
  4. 4.
    McDonald SP, Craig JC (2004) Long-term survival of children with end-stage renal disease. N Engl J Med 350:2654–2662PubMedCrossRefGoogle Scholar
  5. 5.
    Groothoff JW, Gruppen MP, Offringa M, Hutten J, Lilien MR, Van De Kar NJ, Wolff ED, Davin JC, Heymans HS (2002) Mortality and causes of death of end-stage renal disease in children: a Dutch cohort study. Kidney Int 61:621–629PubMedCrossRefGoogle Scholar
  6. 6.
    Wong CS, Gipson DS, Gillen DL, Emerson S, Koepsell T, Sherrard DJ, Watkins SL, Stehman-Breen C (2000) Anthropometric measures and risk of death in children with end-stage renal disease. Am J Kidney Dis 36:811–819PubMedCrossRefGoogle Scholar
  7. 7.
    Wong CS, Hingorani S, Gillen DL, Sherrard DJ, Watkins SL, Brandt JR, Ball A, Stehman-Breen CO (2002) Hypoalbuminemia and risk of death in pediatric patients with end-stage renal disease. Kidney Int 61:630–637PubMedCrossRefGoogle Scholar
  8. 8.
    Furth SL, Hwang W, Yang C, Neu AM, Fivush BA, Powe NR (2002) Growth failure, risk of hospitalization and death for children with end-stage renal disease. Pediatr Nephrol 17:450–455PubMedCrossRefGoogle Scholar
  9. 9.
    KDOQI Work Group (2009) KDOQI Clinical Practice Guideline for Nutrition in Children with CKD: 2008 update. Executive summary. Am J Kidney Dis 53:S11–S104Google Scholar
  10. 10.
    Goldstein SL, Sorof JM, Brewer ED (1999) Evaluation and prediction of urea rebound and equilibrated Kt/V in the pediatric hemodialysis population. Am J Kidney Dis 34:49–54PubMedCrossRefGoogle Scholar
  11. 11.
    Depner TA, Daugirdas JT (1996) Equations for normalized protein catabolic rate based on two-point modeling of hemodialysis urea kinetics. J Am Soc Nephrol 7:780–785PubMedGoogle Scholar
  12. 12.
    Daugirdas JT (1989) The post: pre dialysis plasma urea nitrogen ratio to estimate K.t/V and NPCR: validation. Int J Artif Organs 12:420–427PubMedGoogle Scholar
  13. 13.
    Goldstein SL (2004) Adequacy of dialysis in children: does small solute clearance really matter? Pediatr Nephrol 19:1–5PubMedCrossRefGoogle Scholar
  14. 14.
    Daugirdas JT (1993) Second generation logarithmic estimates of single-pool variable volume Kt/V: an analysis of error. J Am Soc Nephrol 4:1205–1213PubMedGoogle Scholar
  15. 15.
    Goldstein SL, Sorof JM, Brewer ED (1999) Natural logarithmic estimates of Kt/V in the pediatric hemodialysis population. Am J Kidney Dis 33:518–522PubMedCrossRefGoogle Scholar
  16. 16.
    Goldstein SL (2001) Hemodialysis in the pediatric patient: state of the art. Adv Ren Replace Ther 8:173–179PubMedCrossRefGoogle Scholar
  17. 17.
    Borah MF, Schoenfeld PY, Gotch FA, Sargent JA, Wolfsen M, Humphreys MH (1978) Nitrogen balance during intermittent dialysis therapy of uremia. Kidney Int 14:491–500PubMedCrossRefGoogle Scholar
  18. 18.
    Srivaths PR, Wong C, Goldstein SL (2009) Nutrition aspects in children receiving maintenance hemodialysis: impact on outcome. Pediatr Nephrol 24:951–957PubMedCrossRefGoogle Scholar
  19. 19.
    Gotch FA, Sargent JA (1985) A mechanistic analysis of the National Cooperative Dialysis Study (NCDS). Kidney Int 28:526–534PubMedCrossRefGoogle Scholar
  20. 20.
    Casino FG, Lomonte C, Russo R, Di Iorio B, Chiarulli G, Manno C, Lopez T (1995) A modified Two-BUN method for routine urea modeling: clinical validation in 120 patients on a free diet. Int J Artif Organs 18:553–557PubMedGoogle Scholar
  21. 21.
    Orellana P, Juarez-Congelosi M, Goldstein SL (2005) Intradialytic parenteral nutrition treatment and biochemical marker assessment for malnutrition in adolescent maintenance hemodialysis patients. J Ren Nutr 15:312–317PubMedCrossRefGoogle Scholar
  22. 22.
    Juarez-Congelosi M, Orellana P, Goldstein SL (2007) Normalized protein catabolic rate versus serum albumin as a nutrition status marker in pediatric patients receiving hemodialysis. J Ren Nutr 17:269–274PubMedCrossRefGoogle Scholar

Copyright information

© IPNA 2012

Authors and Affiliations

  • Poyyapakkam R. Srivaths
    • 1
  • Scott Sutherland
    • 2
  • Steven Alexander
    • 2
  • Stuart L. Goldstein
    • 3
  1. 1.Renal Section, Department of PediatricsBaylor College of Medicine and Texas Children’s HospitalHoustonUSA
  2. 2.Pediatric NephrologyStanford University Medical CenterStanfordUSA
  3. 3.Pediatric NephrologyCincinnati Children’s HospitalCincinnatiUSA

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