[Diet therapy in preventing the progression of chronic renal insufficiency]. / Terapia dietetica e prevenzione della progressione dell'insufficienza renale cronica.

The effect of a low protein diet (LPD) on the progression of chronic renal insufficiency (CRI) was investigated by reviewing the published studies. Only the trials of Rosman, Ihle and Locatelli fulfilled the main methodological criteria of being randomized, prospective and controlled. They involved 811 patients (671 evaluated: 338 on an LPD, 333 as controls) and had a mean follow-up of 29 months (range 18-48) for an estimated total of about 17,335 patient-months. The only trial whose results showed that LPD had a positive effect on the progression of chronic renal failure (CRF) was Ihle's study with the lowest weight (6.7%) and which involved the most severe CRF; effects limited to the patients with more advanced CRF were found in Roman's study, with an intermediate weight (41.8%); and little effect, if any, in Locatelli's trial accounting for 51.5% of patient-months, with less severe CRI. In conclusion, analysis of published randomized, prospective and controlled trials offers little or no evidence for the hypothesis that an LPD has a greater clinically significant effect on early CRI progression than a controlled protein diet, although a very low protein diet seems to postpone the need for dialysis.

Supplemented low-protein diet and once-weekly hemodialysis.

The aim of this study was to evaluate the feasibility and the nutritional and depurative adequacy of the integrated diet dialysis program. The integrated diet dialysis program consists of a low-protein diet (0.4 g/kg ideal body weight/d), supplemented with essential amino acids or a mixture of essential amino acids and chetoanalogues, and once-weekly hemodialysis, tailored to maintain predialytic blood urea nitrogen levels lower than 90 mg/dL. Sixty-nine of 84 recruited patients with a mean age of 62.9 +/- (SD) 11.1 years and a baseline glomerular filtration rate of 2.54 +/- 0.94 mL/min entered the experimental phase; 15 dropped out, eight because of poor diet compliance. At 12-month follow-up, patient and technique survival were, respectively, 89% and 56%. The laboratory, anthropometric, and instrumental parameters of 28 patients with a follow-up of more than 12 months were also evaluated using repeated measures ANOVA. Mean predialytic blood urea nitrogen values were not significantly different (82 +/- 21 mg/dL v 93 +/- 26 mg/dL at baseline and after 12-month follow-up, respectively); total weekly KT/V from residual renal function plus dialysis (1.64 +/- 0.32 v 1.70 +/- 0.29; P = NS) and dialytic index according to Babb and Scribner (1.35 +/- 0.31 v 1.21 +/- 0.33) were stable. No problems were found as far as acid-base, calcium phosphate, water-electrolyte metabolism and blood pressure control are concerned. Body weight, fat free mass, fat, plasma proteins, albumin, and C3 and C4 complement factors were stable. Creatinine production (sum of metabolized plus excreted creatinine) decreased (14.3 +/- 3.2 mg/kg/d v 13.4 +/- 2.6 mg/kg/d; P < 0.05). Transferrin decreased but not significantly (221 +/- 46 mg/dL v 204 +/- 42 mg/dL; P < 0.09). Distal motor conduction velocity from the posterior tibial nerve did not improve during the study (37.8 +/- 4.9 m/s v 36.4 +/- 4.9 m/s), while distal motor conduction velocity from the median nerve worsened (50.8 +/- 4.3 m/s v 46.3 +/- 6.3 m/s; P < 0.05). In conclusion, even though the integrated diet dialysis program may be very important in the psychologically delicate phase between the conservative and the classical three-times-a-week hemodialysis programs, and may also solve some economic and dialytically related organizational problems, it arouses some concern as far as compliance and long-term nutritional and depurative adequacy are concerned. It should therefore be limited to highly motivated patients in centers with well-trained staff or where dialysis facilities are lacking.

Controlled trials on low-protein diet: effects on chronic renal insufficiency progression.

The effect of a low-protein diet (LPD) on chronic renal insufficiency (CRI) progression was investigated by reviewing the published studies. Only three of these fulfilled the main methodological criteria of being randomized, prospective, and controlled: those of Rosman, Ihle and Locatelli. These trials involved 811 patients (671 evaluated: 338 on a LPD, 333 as controls) and had a mean follow-up of 29 months (range 18-48), for an estimated total of about 17,335 patient-months. The only trial whose results showed that LPD had a positive effect on chronic renal failure (CRF) progression was Ihle's study, with the lowest weight (6.7%) and involving the most severe CRF; effects limited to the patients with more advanced CRF were found in the Rosman study, with an intermediate weight (41.8%); and little effect, if any, was found in the Locatelli trial, accounting for 51.5% of patient-months, with less severe CRI. In conclusion, analysis of published randomized, prospective, and controlled trials offers little or no support for the hypothesis that a LPD has a clinically significant effect on the early CRI progression, although a very low protein diet seems to postpone the need for dialysis.

How to determine ionic dialysance for the online assessment of delivered dialysis dose.

BACKGROUND: Ionic dialysance may be equivalent to blood-water urea clearance corrected for recirculation (effective urea clearance); however, this is controversial. The aims of our study were (1) to verify in vivo whether the value of ionic dialysance is affected by the method of determination, given the effect of cardiopulmonary recirculation on inlet plasma water conductivity when the inlet dialysate conductivity is changed; and (2) to define the operative modalities for determining ionic dialysance to obtain an adequate estimate of effective urea clearance. METHODS: Thirty-three hemodialysis patients were studied during 186 dialysis sessions with low-flux polysulfone dialyzers using a modified Fresenius Medical Care 4008 B machine equipped with meters to measure inlet and outlet dialysate conductivities. This machine varied inlet dialysate conductivity (Cdi) according to the following pattern: starting from baseline (step 0), Cdi was increased by 8% (step 1). After Cdi had reached the target value, which took 8 to 10 minutes, it was lowered to 8% below the baseline value (step 2). After 8 to 10 minutes, when Cdi had reached the new target, it was returned to its starting value (step 3). Four values of conventional ionic dialysance (using the standard formula) and actual ionic dialysance (taking into account cardiopulmonary recirculation) were obtained for each cycle and were compared among them and with effective urea clearance (Kde). RESULTS: Mean conventional dialysance values at steps 0 to 2 and 2 to 3 (190 and 189 mL/min) were similar and higher than those at steps 0 to 1 and 1 to 2 (171 and 181 mL/min). Mean conventional ionic dialysance values underestimated Kde, particularly at steps 0 to 1 (-22.2 mL/min, P < 0.001) and 1 to 2 (-12.6 mL/min, P < 0.001). The actual dialysance values underestimated Kde by no more than 4.3 mL/min (P < 0.001). In steps 0 to 1 and 1 to 2, the underestimate of Kde by conventional dialysance increased at higher values of Kde, but this relationship did not exist when considering actual dialysance. CONCLUSIONS: The value of ionic dialysance is affected by the method of determination, given the effect of cardiopulmonary recirculation on inlet plasma water conductivity when inlet dialysate conductivity is changed. As a consequence, to provide a correct and direct estimate of effective urea clearance, ionic dialysance must be determined by changing inlet dialysate conductivity in such a way as to keep inlet plasma water conductivity constant by means of two symmetrical high and low dialysate conductivity steps.