FEBM and PNA will be measured by creatinine kinetics at 0, 24 and 52 weeks. A 24-hour dialysate and urine collections will be performed. Total and peritoneal Kt/V are determined by standard methods. Residual GFR is calculated as average of 24-hour urinary urea and creatinine clearance. FEBM is calculated according to the formula of Forbes and Brunining [41]. PNA is derived from the Randerson's formula [42]. It is further normalized to standard body weight.