Until recently, the accepted National Kidney Foundation (NKF) K/DOQI guidelines for peritoneal dialysis (PD) adequacy was set to a weekly Kt/Vurea of 2.1.

Data from the Canada-USA (CANUSA) study largely i nfluenced the prior higher Kt/Vurea. The revised NKF K/DOQI guidelines for PD adequacy lowered the Kt/ Vurea from 2.0 to 1.7. This reduction in Kt/Vurea is largely based on two randomized trials. The ADEMEX trial, which took place in Mexico, randomized incident and prevalent patients into 2 groups with 2 levels of PD prescription. The study did not find a difference in survival outcome between the groups suggesting no added survival benefit for greater small-molecule peritoneal clearance. A second randomized trial in Hong Kong compared 3 levels of total Kt/Vurea in new patients with reduced residual kidney function and also found no difference in survival.

According to recent USRDS data in 2003, there were over 11,281 patients receiving continuous ambulatory PD (CAPD) and 14,544 receiving continuous PD. CAPD and continuous PD accounted for over 3.5 and 4.5% of all patients on renal replacement therapy, respectively. The majority of patients receiving PD were between the ages of 45-64 years accounting for 43%, followed by patients between the ages of 20-44 years (23%). Whites, Blacks and Asians accounted for roughly 65, 26 and 6% of all patients on PD, respectively.

The odds of having a body mass index (BMI) above 30 has increased in incident end-stage renal disease patients.


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James F. Winchester

Division of Nephrology and Hypertension, Beth Israel Medical Center Baird Hall, 18BH26, 350 East 17th Street New York, NY 10003 (USA)

Tel. +1 212 420 4070, Fax +1 212 420 4117, E-Mail [email protected]

White patients experienced 82% higher odds of having a BMI of >30 in 2002-2004 compared to 1996-1998. For Blacks the odds doubled.

Differences in body weight, morphology and mor-phometry must be considered in the interpretation of measures of adequacy in PD. The K/DOQI recommendations for adequate delivery of dialysis include weekly creatinine clearance normalized to a body surface area (BSA) of 1.73 m2 as well as weekly Kt/V, with clearance normalized to body volume.

With Kt/V, the V represents the volume of distribution (in liters) of urea. Volume of distribution (Vd) of urea for calculating Kt/V is determined by anthropomorphic estimations of total body water using either the Watson or Hume-Weyers methods (for adults, by sex) or the Mellits-Cheek method (for children, by sex). All of the estimating formulae for total body water are based on measurements of an individual patient's height and weight. As the formulae for BMI and BSA also depend solely on height and weight, patients with larger BMIs will in turn have larger total body water (and V) as well as BSA. How this increase in V and BSA correlates with peritoneal surface area is uncertain.

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