Supplemented very low protein diet ameliorates responsiveness to erythropoietin in chronic renal failure.
BACKGROUND
The aim of this study was to evaluate the relationship between uremic state and erythropoiesis in patients with predialytic chronic renal failure (CRF).


METHODS
We monitored for 2 years the erythropoietin (EPO) requirement in patients with advanced CRF (creatinine clearance < or =25 mL/min), randomized to either low protein diet (LPD) group (0.6 g/kg body weight/day, N = 10) or very low protein diet (VLPD) group (0.3 g/kg body weight/day, N = 10) supplemented with a mixture of ketoanalogs and essential amino acids, both kept at target hemoglobin levels.


RESULTS
The achieved protein intake after 6 months was 0.79 +/- 0.02 g/kg body weight/day and 0.50 +/- 0.02 g/kg body weight/day in LPD and VLPD, respectively; such a difference was maintained up to the end of follow up. The final hemoglobin values did not differ from the basal values in either group (11.5 +/- 0.2 g/dL and 11.5 +/- 0.3 g/dL). EPO dose, that was similar at baseline (62.4 +/- 9.6 UI/kg body weight/week and 61.8 +/- 8.8 UI/kg body weight/week subcutaneously), remained unchanged in LPD but progressively decreased in VLPD down to the final value of 41.2 +/- 7.0 UI/kg body weight/week (P < 0.0001 vs. basal and LPD). VLPD was associated with a decrease of urinary excretion and serum levels of urea nitrogen and phosphate; however, EPO requirement was not correlated with the changes of these parameters. On the contrary, the variation of EPO dose directly correlated with the modification of parathyroid hormone (PTH) levels, that diminished from 229 +/- 55 pg/mL to 118 +/- 16 pg/mL (P < 0.0001) in VLPD and did not change in LPD.


CONCLUSIONS
In patients with advanced CRF, an effective decrease of protein intake of 0.3 g/kg body weight/day induces a reduction of about 35% of the EPO dose required to maintain the target hemoglobin levels. This effect appears dependent on the correction of a moderate secondary hyperparathyroidism.
Di Iorio
Biagio R
BR
Department of Nephrology-School of Medicine, Second University of Naples, Naples, Italy.
Minutolo
Roberto
R
De Nicola
Luca
L
Bellizzi
Vincenzo
V
Catapano
Fausta
F
Iodice
Carmela
C
Rubino
Roberto
R
Conte
Giuseppe
G
D000328:Adult; D000368:Aged; D000740:Anemia / Q000188:drug therapy* / Q000209:etiology; D018753:Diet, Protein-Restricted; D004044:Dietary Proteins / Q000008:administration & dosage; D004921:Erythropoietin / Q000008:administration & dosage*; D005260:Female; D005500:Follow-Up Studies; D006454:Hemoglobins; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications* / Q000178:diet therapy*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D014511:Uremia / Q000150:complications / Q000178:diet therapy
D004044:Dietary Proteins; D006454:Hemoglobins; D004921:Erythropoietin