Comparisons of isonitrogenous supplements (1.2 g N) of essential amino acids and five keto acid analogues with four essential amino acids were made in seven patients with stable chronic renal failure (creatinine clearance, 4.6 to 16 ml/min) on moderately protein-restricted diets (4.60 to 7.8 g N per day). Full nitrogen balance data on the four patients who have already completed studies lasting 24 weeks are presented. No benefits of keto acid over amino acid supplements were observed. Two transient episodes of hypercalcemia occurred during keto acid treatment. There was no improvement of renal function with keto acids. Also, no carry-over effects were seen after keto acid treatment. It is concluded that any beneficial effects of keto acids in patients with chronic renal failure are only likely to occur in those taking a diet of less than 30 g protein daily.

6 patients in end-stage renal failure of varying aetiologies have been studied on low protein dietary regimens according to a P 6 formulation. All patients had part of their daily protein allowance substituted by an essential amino acid capsule also containing histidine and glutamic acid. All patients were maintained in nutritional balance as a result of the regimens prescribed. No toxic effects were noted and patient compliance was good. Our studies suggest the amino acid formulation given is safe and did not cause any fluctuations in patient plasma amino acid profiles. Our studies suggest an improved method of low protein dietary management for chronic renal failure patients together with a greater flexibility and wider range of prescribing possibilities. It is recommended that amino acid supplements according to the formula produced here constitute an improvement on currently prescribed Giovannetti regimens.

Six patients with stable end stage chronic renal failure have been studied while receiving keto-acid supplements that provided a daily calcium load of 42 +/- 2 mM. None of the patients had intercurrent illness. All patients showed elevated serum calcium concentration levels while on keto-acid supplements, reaching significance on 5 occasions. Reciprocal falls in serum phosphate concentrations were noted in all patients, and this observation was not due to an anabolic effect of the keto-acids. In 3 patients, the rise in serum calcium concentration was associated with marked clinical manifestations that required curtailment of treatment. The risk of hypercalcemia occurs early and certain high risk categories can be identified. Recommendations about the use of calcium salts of alpha-keto-acid analogues are given and it is suggested that a choice should be made available between calcium and sodium salt analogues.

Summary The addition of amino acid supplements to peritoneal dialysis fluid has been studied in 8 patients with compromised renal function requiring peritoneal dialysis. By the addition of 10 ml of Vamin-glucose solution to each one litre of peritoneal dialysate, amino acid losses were curtailed, no significant alterations occurred in the plasma amino acid concentrations, there were no local complications and no infections were seen. This procedure is recommended as a safe, simple way of keeping a patient in positive amino acid balance during peritoneal dialysis.