Effects of a Supplemented Hypoproteic Diet in Chronic Kidney Disease

Objective

We assessed the effect of a severe hypoproteic diet supplemented with ketoanalogues (SVLPD) for 48 weeks on certain metabolic disorders of chronic kidney disease (CKD).

Design

We performed a prospective, open-label, parallel, randomized, controlled trial.

Setting

The study took place in the Nephrology Department at the Dr Carol Davila Teaching Hospital of Nephrology, Bucharest, Romania.

Patients

A total of 53 nondiabetic patients with CKD with an estimated glomerular filtration rate less than 30 mL/min/1.73 m² (Modification of Diet in Renal Disease formula), proteinuria less than 1 g/g urinary creatinine, good nutritional status, and anticipated good compliance with the diet were randomly assigned to two groups.

Intervention

Group I (n = 27) received the SVLPD (0.3 g/kg/d of vegetable proteins and ketoanalogues, 1 capsule for every 5 kg of ideal body weight per day). Group II (n = 26) continued a conventional low mixed protein diet (0.6 g/kg/d).

Outcome Measures

Nitrogen waste products retention and calcium-phosphorus and acid-base disturbances were primary efficacy parameters, and “death” of the kidney or the patient and the estimated glomerular filtration rate were secondary efficacy parameters. The nutritional status and compliance with the diet were predefined as safety variables. There were no differences between groups in any parameter at baseline.

Results

In the SVLPD group, serum urea significantly decreased (56 ± 7.9 mmol/L vs. 43.2 ± 10 mmol/L), and significant improvements in serum bicarbonate (23.4 ± 2.1 mmol/L vs. 18.1 ± 1.5 mmol/L), serum calcium (1.10 ± 0.17 mmol/L vs. 1.00 ± 0.15 mmol/L at baseline), serum phosphates (1.45 ± 0.66 mmol/L vs. 1.91 ± 0.68 mmol/L), and calcium-phosphorus product (1.59 ± 0.11 mmol²/L² vs. 1.91 ± 0.10 mmol²/L²) were noted after 48 weeks. No death was registered in any group. Significantly lower percentages of patients in group I required renal replacement therapy initiation (4% vs. 27%). After 48 weeks, estimated glomerular filtration rate did not significantly change in patients receiving SVLPD (0.26 ± 0.08 mL/s vs. 0.31 ± 0.08 mL/s at baseline), but significantly decreased in controls (0.22 ± 0.09 mL/s vs. 0.30 ± 0.07 mL/s). The compliance with the keto-diet was good in enrolled patients. No significant changes in any of the parameters of the nutritional status and no adverse reactions were noted.

Conclusion

SVLPD seems to ameliorate the nitrogen waste products retention and acid-base and calcium-phosphorus metabolism disturbances and to postpone the renal replacement therapy initiation, preserving the nutritional status in patients with CKD.