Better preservation of residual renal function in peritoneal dialysis patients treated with a low-protein diet supplemented with keto acids: a prospective, randomized trial.

Abstract

BACKGROUND:

While a low-protein diet may preserve residual renal function (RRF) in chronic kidney disease (CKD) patients before the start of dialysis, a high-protein intake is usually recommended in dialysis patients to prevent protein-energy wasting. Keto acids, which were often recommended to pre-dialysis CKD patients treated with a low-protein diet, had also been reported to be associated with both RRF and nutrition maintenance. We conducted a randomized trial to test whether a low-protein diet with or without keto acids would be safe and associated with a preserved RRF during peritoneal dialysis (PD).

METHODS:

To assess the safety of low protein, we first conducted a nitrogen balance study in 34 incident PD patients randomized to receive in-centre diets containing 1.2, 0.9 or 0.6 g of protein/kg ideal body weight (IBW)/day for 10 days. Second, 60 stable PD patients [RRF 4.04 +/- 2.30 ml/ min/1.73 m(2), urine output 1226 +/- 449 ml/day, aged 53.6 +/- 12.8 years, PD duration 8.8 (1.5-17.8) months] were randomized to receive either a low- (LP: 0.6-0.8 g/kg IBW/day), keto acid-supplemented low- (sLP: 0.6-0.8 g/kg IBW/day with 0.12 g/kg IBW/day of keto acids) or high-protein (HP: 1.0-1.2 g/kg IBW/day) diet. The groups were followed for 1 year and RRF as well as nutritional status was evaluated serially.

RESULTS:

A neutral or positive nitrogen balance was achieved in all three groups. RRF remained stable in group sLP (3.84 +/- 2.17 to 3.39 +/- 3.23 ml/min/1.73 m(2), P = ns) while it decreased in group LP (4.02 +/- 2.49 to 2.29 +/- 1.72 ml/min/1.73 m(2), P < 0.05) and HP (4.25 +/- 2.34 to 2.55 +/- 2.29 ml/min/1.73 m(2), P < 0.05). There was no change from baseline on nutritional status in any of the groups during follow-up.

CONCLUSIONS:

A diet containing 0.6-0.8 g of protein/kg IBW/day is safe and, when combined with keto acids, is associated with an improved preservation of RRF in relatively new PD patients without significant malnutrition or inflammation.

• Authors: Na Jiang, Jiaqi Qian, Weilan Sun, Aiwu Lin, Liou Cao, Qin Wang, Zhaohui Ni, Yanping Wan, Bengt Linholm, Jonas Axelsson, Qiang Yao
• Journal: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association (Nephrol Dial Transplant) Vol. 24 Issue 8 Pg. 2551-8 (Aug 2009) ISSN: 1460-2385 [Electronic] England
• PMID: 19258386 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Dietary Proteins
• Keto Acids
• Nitrogen

Topics

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Dietary Proteins (administration & dosage)
• Dietary Supplements
• Female
• Follow-Up Studies
• Humans
• Keto Acids (metabolism)
• Kidney Failure, Chronic (diet therapy, metabolism)
• Kidney Function Tests
• Male
• Middle Aged
• Nitrogen (metabolism)
• Peritoneal Dialysis (methods)
• Prospective Studies
• Tissue Distribution
• Young Adult