title: The contribution of residual renal function to overall nutritional status in chronic haemodialysis patients.
abstract: BACKGROUND
  The benefits of residual renal function (RRF) in peritoneal dialysis patients have been described frequently. However, previous reports have shown that RRF diminished faster in haemodialysis (HD) patients than in peritoneal dialysis patients, and in most of the studies in HD patients, RRF was ignored. In this study, the RRF in chronic HD patients was studied to assess its impact on patients' nutritional status.
  
  
  METHODS
  In 41 chronic HD patients with at least a 2-year history of HD treatment, RRF was determined by a urine collection for 7 consecutive days. Nutritional parameters, such as percentage body fat, fat-free mass index, serum albumin concentration and normalized protein catabolic rate, were also measured.
  
  
  RESULTS
  In all 41 patients, mean weekly total Kt/V urea was 4.88 and renal Kt/V urea was 0.65. RRF was well correlated with serum albumin concentration, but dialysis Kt/V urea was not. One year after the start of this study, RRF and nutritional indices were re-examined and patients were classified into two groups: with RRF, preserved residual renal diuresis over 200 ml/day (mean, 720 ml; range, 230-1640 ml), N=23; and without RRF, persistent anuria (mean, 51 ml; range, 0-190 ml), N=18. At the start of this study, the mean serum albumin concentration and mean normalized protein catabolic rate in patients with RRF were 3.84 g/dl and 1.16 g/kg/day, respectively, which were significantly higher than those in patients without RRF (P=0.02 and P=0.0002, respectively), despite total (renal+dialysis) Kt/V urea being equal in both groups. During the 1-year study period, there was no significant change in total Kt/V urea in either group. Mean serum albumin concentration increased to 4.05 g/dl in patients with RRF, but did not change significantly (from 3.66 to 3.62 g/dl) in patients without RRF. The same trend was observed in all other parameters.
  
  
  CONCLUSIONS
  Over half of our HD patients had sufficient RRF. RRF itself may have a beneficial effect on nutritional parameters, and it is important to determine RRF over time, even in chronic HD patients.
authors.affiliation: Second Department of Internal Medicine, School of Medicine, University of Environmental and Occupational Health, Fukuoka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suda
authors.forename: K
authors.initials: K
authors.lastname: Hiroshige
authors.forename: T
authors.initials: T
authors.lastname: Ohta
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Iwamoto
authors.forename: K
authors.initials: K
authors.lastname: Kanegae
authors.forename: A
authors.initials: A
authors.lastname: Ohtani
authors.forename: Y
authors.initials: Y
authors.lastname: Nakashima
mesh_terms: D000368:Aged; D003404:Creatinine / Q000493:pharmacokinetics; D004231:Diuresis; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D006435:Renal Dialysis; D012709:Serum Albumin / Q000032:analysis; D013997:Time Factors; D014508:Urea / Q000493:pharmacokinetics
chemical_list: D012709:Serum Albumin; D014508:Urea; D003404:Creatinine