Exploring the reverse J-shaped curve between urea reduction ratio and mortality (original) (raw)

Abstract

malnutrition (manifest by a reduced V) that overcomes what-Exploring the reverse J-shaped curve between urea reduction ever benefit might be derived from an associated increase in urea ratio and mortality. clearance. Identification of patients who achieve extremely Background. Although accepted worldwide as valid meahigh URR (Ͼ75%) or single-pooled Kt/V (Ͼ1.6) values using sures of dialysis adequacy, neither the Kt/V (urea clearance standard dialysis prescriptions should prompt a careful assessdetermined by kinetic modeling) nor the urea reduction ratio (URR) have unambiguously predicted survival in hemodialysis ment of nutritional status. Confounding by protein-calorie malpatients. Because the ratio Kt/V can be high with either high nutrition may limit the utility of URR or Kt/V as a population-Kt (clearance ϫ time) or low V (urea volume of distribution) based measure of dialysis dose. and V may be a proxy for skeletal muscle mass and nutritional health, we hypothesized that the increase in the relative risk of death observed among individuals dialyzed in the top 10 to Defining the dose of dialysis to optimize health and 20% of URR or Kt/V values might reflect a competing risk of malnutrition. functional status for patients with end-stage renal disease Methods. A total of 3,009 patients who underwent bioelec-(ESRD) has been among the principle goals of the netrical impedance analysis were stratified into quintiles of URR. phrology community for more than two decades. In a Laboratory indicators of nutritional status and two bioimpelandmark publication in 1985, Gotch and Sargent revoludance-derived parameters, phase angle and estimated total tionized the field of dialysis therapy with their reanalysis body water, were compared across quintiles. The relationship between dialysis dose and mortality was explored, with a focus of data from the National Cooperative Dialysis Study on how V influenced the structure of the dose-mortality rela-(NCDS) [1, 2], redefining the dose of dialysis in terms tionship. of the clearance (K) ϫ time (t) product normalized to Results. There were statistically significant differences in all the urea volume of distribution (V), a dimensionless nutritional parameters across quintiles of URR or Kt/V, indiquantity derived from the fractional reduction in urea cating that patients in the fifth quintile (mean URR, 74.4 Ϯ 3.1%) were more severely malnourished on average than panitrogen (URR) achieved over the course of a hemodialtients in all or some of the other quintiles. The relationship ysis treatment. These authors and others who followed between URR and mortality was decidedly curvilinear, resemthem were successful at identifying a minimum dose of bling a reverse J shape that was confirmed by statistical analysis. dialysis above which death and complications were less An adjustment for the influence of V on URR or Kt/V was performed by evaluating the Kt-mortality relationship. There likely, although the optimal dose of dialysis remained was no evidence of an increase in the relative risk of death unknown. Application of this methodology to other paamong patients treated with high Kt. Higher Kt was associated tient cohorts similarly showed that an increase in URR with a better nutritional status. or Kt/V was generally associated with reduced mortality Conclusion. We conclude that the increase in mortality oband less frequent complications [3-8]. Although it folserved among those patients whose URR or Kt/V are among the top 10 to 20% of patients reflects a deleterious effect of lowed that further increases in dialysis dose might be expected to lead to fewer complications and better outcomes, Owen et al initially showed that there appeared

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References (19)

  1. Chertow GM, Lazarus JM, Lew NL, Ma L, Lowrie EG: Develop- ment of a population-specific regression equation to estimate total 329:1001-1006, 1993 body water in hemodialysis patients. Kidney Int 51:1578-1582, 1997
  2. Collins AJ, Ma JZ, Umen A, Keshaviah P: Urea index (Kt/V) 17. Kleinbaum DG, Kupper LL, Muller KE: One-way analysis of and other predictors of hemodialysis patient survival. Am J Kidney variance, in Kleinbaum DG, Kupper LL, Muller KE, Applied Dis 23:272-282, 1994 Regression Analysis and Other Multivariable Methods, Belmont,
  3. Hakim RM, Breyer J, Ismail N, Schulman G: Effects of dose of Duxbury Press, 1988, pp 361-374
  4. dialysis on morbidity and mortality. Am J Kidney Dis 23:661-669, 18. Cox DR: Regression models and life tables. J Royal Stat Soc B 1994 74:187-220, 1972
  5. Parker TF, Husni L, Huang W, Lew N, Lowry W: Survival of 19. Collett D: Modelling survival data in medical research. London, hemodialysis patients in the United States is improved with a Chapman & Hall, 1994 pp 149-197 greater quantity of dialysis. Am J Kidney Dis 23:670-680, 1994 20. Maggiore Q, Nigrelli S, Ciccarelli C, Grimaldi C, Rossi GA,
  6. Held PJ, Port FK, Wolfe RA, Stannard DC, Daugirdas JT, Michelassi C: Nutritional and prognostic correlates of bio- Bloembergen WE, Greer JW, Hakim RM: The dose of dialysis impedance indexes in hemodialysis patients. Kidney Int 50:2103- and patient mortality. Kidney Int 50:550-556, 1996 2108, 1996
  7. Hemodialysis Adequacy Work Group: NKF-DOQI clinical prac- 21. Chertow GM, Jacobs DO, Lazarus JM, Lew NL, Lowrie EG: tice guidelines for hemodialysis. Am J Kidney Dis 30(Suppl):S15- Phase angle predicts survival in hemodialysis patients. J Renal Nutr S66, 1997 7:204-207, 1997
  8. McClellan WM, Soucie JM, Flanders WD: Mortality in end- 22.
  9. Gunnell J, Yeun JY, Depner TA, Kaysen GA: Acute-phase stage renal disease is associated with facility-to-facility differences response predicts erythropoetin resistance in hemodialysis and in the adequacy of hemodialysis. J Am Soc Nephrol 9:1940-1947, peritoneal dialysis patients. Am J Kidney Dis 33:63-72, 1999 1998 23. Department of Health and Human Services: 1998: ESRD Core 10.
  10. Frankenfield D, McClellan WM, Helgerson S, Lowrie EG, Indicators Project. Bethesda, Health Care Financing Administra- Rocco M, Owen WF: Relationship between urea reduction ratio, tion, Health Standards and Quality Bureau, February, 1999 demographic characteristics, and body weight for patients in the 24. Chertow GM, Lazarus JM, Lew NL, Ma L, Lowrie EG: Bio- 1996 National ESRD Core Indicators Project. Am J Kidney Dis impedance norms for the hemodialysis population. Kidney Int 33:584-591, 1999 52:1617-1621, 1997
  11. Chertow GM, Lowrie EG, Wilmore DW, Gonzalez J, Lew NL, 25. Owen WF, Chertow GM, Lazarus JM, Lowrie EG: The dose
  12. Ling J, LeBoff MS, Gottlieb MN, Huang W, Zebrowski B, of hemodialysis: Survival differences by sex and race. JAMA
  13. College J, Lazarus JM: Nutritional assessment using bioelectrical 280:1764-1768, 1998
  14. impedance analysis in maintenance hemodialysis patients. J Am 26. Aloia JF, Vaswani A, Flaster E, Ma R: Relationship of body Soc Nephrol 6:75-81, 1995 water compartments to age, race, and fat-free mass. J Lab Clin 12. Lukaski HC, Johnson PE, Bolonchuk WW, Lykken GI: Assess- Med 132:483-490, 1998
  15. ment of fat-free mass using bioelectrical impedance measurements 27. Owen WF, Meyer K, Schmitt G, Alfred H, the Medical Review of the human body. Am J Clin Nutr 41:810-817, 1985 Board of the ESRD Network of New England: Methodological
  16. Lowrie EG, Lew NL: Death risk in hemodialysis patients: The limitations of the ESRD Core Indicators Project: An ESRD Net- predictive value of commonly measured variables and an evalua- work's experience with implementing an ESRD quality survey. tion of death rate differences between facilities. Am J Kidney Dis Am J Kidney Dis 30:349-355, 1997 15:458-482, 1990
  17. Leblanc M, Charbonneau R, Lalumiere G, Cartier P, Deziel C:
  18. Watson PE, Watson ID, Batt RD: Total body water volumess Postdialysis urea rebound: Determinants and influence of dialysis for adult males and females estimated from simple anthorpometric delivery in chronic hemodialysis patients. Am J Kidney Dis 27:253- measurements. Am J Clin Nutr 33:27-39, 1980 261, 1996
  19. Hume R, Weyers E: Relationship between total body water and 29. Linday RM, Spanner E: A hypothesis: The protein catabolic rate surface area in normal and obese subjects. J Clin Pathol 24:234-238, is dependent upon the type and amount of treatment in dialyzed uremic patients. Am J Kidney Dis 13:382-389, 1989