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The effect of high-flux hemodialysis membranes on patient survival has not been unequivocally determined. In this prospective, randomized clinical trial, we enrolled 738 incident hemodialysis patients, stratified them by serum albumin < or = 4 and >4 g/dl, and assigned them to either low-flux or high-flux membranes. We followed patients for 3 to 7.5 yr. Kaplan-Meier survival analysis showed no significant difference between high-flux and low-flux membranes, and a Cox proportional hazards model concurred. Patients with serum albumin < or = 4 g/dl had significantly higher survival rates in the high-flux group compared with the low-flux group (P = 0.032). In addition, a secondary analysis revealed that high-flux membranes may significantly improve survival of patients with diabetes. Among those with serum albumin < or = 4 g/dl, slightly different effects among patients with and without diabetes suggested a potential interaction between diabetes status and low serum albumin in the reduction of risk conferred by high-flux membranes. In summary, we did not detect a significant survival benefit with either high-flux or low-flux membranes in the population overall, but the use of high-flux membranes conferred a significant survival benefit among patients with serum albumin < or = 4 g/dl. The apparent survival benefit among patients who have diabetes and are treated with high-flux membranes requires confirmation given the post hoc nature of our analysis.

Dialysis dose ( Kt/V ) remained constant in both groups (from 1.30±0.17 to 1.33±0.20 in the conventional Background. Anaemia is one of the major clinical group and from 1.28±0.26 to 1.26±0.21 in the expericharacteristics of patients with chronic renal failure, mental group, P=0.242). Median pre- and postand has a considerable effect on morbidity and mortal- dialysis b 2 -microglobulin levels remained constant in ity. Adequate dialysis is of paramount importance in the conventional group (31.9 and 34.1 mg/dl at basecorrecting anaemia by removing small and medium- line) and decreased in the experimental group (presized molecules, which may inhibit erythropoiesis. dialysis values from 31.1 to 24.7 mg/dl, P=0.004 and However, high-molecular-weight inhibitors cleared post-dialysis values from 24.8 to 20.8 mg/dl, P= only by means of highly porous membranes have also 0.002). Median erythropoietin doses were not different been found in uraemic serum and it has been claimed at baseline (70 IU/kg/week in conventional treatment from uncontrolled studies that high-flux dialysis could and 90 IU/kg/week in experimental treatment, P= improve anaemia in haemodialysis patients. 0.628) and remained constant during follow-up (from Methods. We therefore planned this multicentre ran- 70 to 69 IU/kg/week in the conventional group and domized controlled trial with the aim of testing whether from 90 to 91 IU/kg/week in the experimental group, the use of a large-pore biocompatible membrane for a P=0.410). Median erythropoietin plasma levels were fixed 12-week follow-up improves anaemia in haemo- in the normal range and remained constant (from 12.1 dialysis patients in comparison with the use of a to 12.9 mU/ml in the conventional group and from conventional cellulose membrane. Eighty-four (5.3%) 13.2 to 14.0 mU/ml in the experimental group, P= of a total of 1576 adult haemodialysed patients 0.550). attending 13 Dialysis Units fulfilled the entry criteria Conclusions. This study showed no difference in haeand were randomly assigned to the experimental treat- moglobin level increase between patients treated for 3 ment (42 patients) or conventional treatment (42 months with a high-flux biocompatible membrane in patients). comparison with those treated with a standard memResults. Haemoglobin levels increased non- brane. When patients are highly selected, adequately significantly from 9.5±0.8 to 9.8±1.3 g/dl (P=0.069) dialysed, and have no iron or vitamin depletion, the in the population as a whole, with no significant effect of a high-flux membrane is much less than might difference between the two groups (P=0.485). be expected from the results of uncontrolled studies. Erythropoietin therapy was given to 32/39 patients Keywords: anaemia; biocompatibility; biocompatible (82%) in the conventional group, and 26/35 (74%) in membrane; cellulose membrane; high-flux haemodiathe experimental group (P=0.783) with subcutaneous lysis; b 2 -microglobulin administration to 26/32 patients in conventional and to 23/26 patients in experimental group, P=0.495.

The stability of the potassium ( K+) body pool in number of patients, their body weight, residual diuresis healthy individuals is maintained by the renal regu- and daily stool excretion are listed. latory excretion of K+. The transient increase in kalae- In healthy individuals without any diet restriction, mia, following a K+ load, first induces a transfer of the K+ intake, the K+ body pool and the renal K+ K+ through the Na+/K+ pump from the extracellular excretion are related to body weight. Consequently, water ( W e ) to the intracellular water ( W i ), and after we related our results to the body weight of our that the K+ load is excreted by the renal tubular cells. patients. The failure of K+ renal excretion in end-stage renal The daily Kd was also calculated, from our data, in disease causes K+ retention, and dangerous hyperkal- order better to compare the intermittent haemodialytic aemia develops; consequently, K+ removal by dialysis schedules with the continuous PD. is mandatory. Knowing the pre- and post-dialytic kalaemia and We performed a retrospective study to investigate the patient’s body weight, the dialytic K+ removal how diVerent dialytic schedules aVect the K+ body from W i ( Kdi) was calculated from the dialytic K+ pool and control the interdialytic kalaemia. removal during each dialytic session, using Gotch’s formula [2]. The appropriate Student’s t-test for the analysis of Materials and methods statistical significance was used. We compared the following diVerent dialytic schedules: peritoneal dialysis (PD), standard haemodialysis Results (HD), pre-dilutional haemofiltration (pre-HF ), postdilutional haemofiltration (post-HF ) and variable-K+ Table 3 summarizes the results from the study. In our HD ( VHD). The K+ concentration in the dialytic bath patients, the pre-dialytic kalaemia ( K B pre) was signiand infusion solution was 0 mEq/l in PD, 2 mEq/ li n ficantly higher in HD than in PD (P

Effect of on-line conductivity plasma ultrafiltrate kinetic modeling on cardiovascular stability of hemodialysis patients. The aim of this multicenter, prospective, randomized cross-over study was to clarify whether on-line conductivity ultrafiltrate kinetic modeling (treatment B), as a substitute for sodium kinetic modeling, is capable of reducing intradialytic cardiovascular instability in comparison with standard treatment (treatment A), by reducing the sodium balance variability. Both treatments were performed by means of a modified hemodiafiltration technique. Treatment A was performed using fixed dialysate conductivity; treatment B made use of the dialysate conductivity derived from a conductivity kinetic model, in order to obtain an end-dialysis ultrafiltrate conductivity at each dialysis session that was equal to the mean value determined in the same patient during the four-week run-in period. Thus, during treatment B, the expected end-dialysis ultrafiltrate conductivity value of each patient should have been constant. The study was carried out according to a multicenter cross-over design of 16 weeks with two treatments (A or B), two sequences (1 = ABB and 2 = BAA), a run-in period of four weeks (period 1, treatment A), and three consecutive experimental periods of four weeks each. Analysis of variance for a cross-over design was used for the statistical analysis. Forty-nine hemodialysis patients prone to intradialytic hypotension (> 25% of sessions) were enrolled from 16 participating centers, and randomly assigned to either sequence 1 (26 patients) or sequence 2 (23 patients). Six patients dropped out and four were protocol violators, which left 39 patients selected for statistical analysis. There was no difference in the average dialysate conductivity, predialysis and end-dialysis plasma water ultrafiltrate conductivity or body weight between treatment A and treatment B. Thus, the observed mean sodium balance was not different and, as expected, only the intra-patient variability of end-dialysis ultrafiltrate conductivity (index of sodium balance variability) was reduced (21%). During treatment A, systolic blood pressure decreased by 23 mm Hg (95% confidence intervals 21 to 24 mm Hg) at the end of dialysis with respect to the pre-dialysis values. Treatment B reduced this intradialytic decrease (P = 0.001) with a maximum effect at the third hour of dialysis (4.4 mm Hg, 95% confidence intervals 1.9 to 6.9 mm Hg, 23% less than during treatment A, P 0.0005) without any period or carry-over effect (P = 0.53 and 0.08, respectively). There was no treatment effect on intradialytic diastolic blood pressure (P = 0.291). In conclusion, intradialytic cardiovascular stability was significantly improved by matching the interdialytic sodium load with intradialytic sodium removal using on-line conductivity ultrafiltrate kinetic modeling as an alternative to sodium kinetic modeling. Although highly significant, this effect was clinically not very large. By applying this conductivity kinetic model to patients with a more variable sodium intake from one session to another, a greater benefit can be expected.

Convective transport across dialysis membranes has been known for a long time to be a good alternative to diffusion. Predilution hemofiltration (HF) offers a better clearance of small molecules and overcomes the blood viscosity problems related to conventional postdilution HF treatment. Three patients have performed a total of 293 predilution HF treatment with AK 100 ULTRA. The bicarbonate substitution fluid has been prepared on-line by the machine. The treatments have been well tolerated and no adverse patients reactions related to the quality of the substitution fluid or the predilution HF treatment have been observed. There is a drop in creatinine for all patients indicating an improved creatinine clearance. Bicarbonate predilution HF has been shown to be a safe and efficient treatment modality, it offers the possibility to improve the cardiovascular stability of patients having problems with other treatment modalities an it offers an improved intertreatment well-being for the patients.

Background: Geographical differences in disease prevalence and mortality have been described in the general population and in chronic kidney disease patients in Europe. In this secondary analysis of the Membrane Permeability Outcome (MPO) study, we addressed differences in patient and treatment patterns, and whether these affect patient outcomes. Methods: Participating countries were grouped according to geographical location; thus study centers in France, Greece, Italy, Portugal and Spain were allocated to southern Europe (n=499), and those in all other countries (Belgium, Germany, Poland and Sweden) to northern Europe (n=148). Descriptive analysis of patient and treatment patterns at study start, as well as survival analysis, was performed. Results: In patients from the northern European countries, a higher prevalence of diabetes mellitus and of cardiovascular disease was observed than in those from southern Europe (diabetes 35.1% vs. 21.0%, p=0.0007; cardiovascular disease 40.5% vs. 22.8%, p

The aim of this study is to evaluate the relationship between two different procedures for potassium removal during hemodialysis (HD) and cardiac arrhythmias. Cell excitability and the transmission of impulses may be influenced by variations of resting membrane potential (RMP). The rapid decrease of plasma potassium during the first two hours of standard HD causes a membrane hyperpolarization. A different K+ kinetic, with a gradual and constant elimination of K+ during HD, may reduce this further unphysiological aspect and its clinical consequences. This can be obtained keeping blood-dialysate K+ gradient as constant as possible with the use of a dialysate K+ concentration (Kd) decreasing during HD. Our experimental studies on various K+ intradialytic gradients seem to indicate as optimal to this purpose K+ gradients of 1.5 mEq/l at the beginning of dialysis, esponentially decreasing during treatment to Kd values of 2.5 mEq/l at the end of dialysis (variable Kd). Patients included in the trial will be submitted to two different methods of treatment with Kd 2 mEq/l and variable Kd, and to a 24 hours ECG the day of dialysis. We will compare the number of intra and interdialytic premature ventricular complexes to evaluate the impact of two different models of potassium removal on arrhythmias.

The aim of this study was to evaluate the role of blood pressure in the progression of chronic renal failure (CRF) in polycystic kidney disease, by analysing the behaviour of 74 affected patients, out of 456 CRF patients with various underlying nephropathies enrolled in a multicentre, formal prospective trial aimed at clarifying the role of protein restriction in retarding CRF progression. Because no difference was found between the patients on a low protein and those on a controlled protein diet, an inductive analysis was made by separating all of the patients into fast progressive or slowly progressive CRF groups. Hypertensive patients were defined as those with a mean resting blood pressure of more than 107 mmHg; of the 62 polycystic patients who completed the study or who reached an end point, 41 patients were hypertensive and 21 normotensive (10 of whom were pharmacologically controlled). The results of the stratified analysis, taking into account the degree of renal function deterioration and the underlying disease, showed a significant relationship between hypertension and CRF progression only in patients with polycystic kidney disease.

The aim of this multicenter prospective study was to investigate the role of relative blood volume (RBV) reduction on intradialytic hypotension.One hundred twenty-three patients on chronic hemodialysis therapy were considered a priori normotensive (reference group A), intradialytic hypotension prone (group B), and hypertensive (group C). RBV was continuously monitored, and diastolic and systolic blood pressure (SBP) and heart rate (HR) were measured at 20-minute intervals during three dialysis sessions.Intradialytic RBV reduction was -13.8% +/- 7.0% and similar in the three groups (P = 0.841). SBP and RBV decreased during dialysis, with a sharp initial decrease (in the first 20 minutes for SBP and the first 40 minutes for RBV), followed by a slower decrease. The lying bradycardic response before dialysis was less in group B than group A (a decrease of 3 +/- 7 versus 9 +/- 9 beats/min; P0.001). When symptomatic hypotension occurred, RBV reduction was not significantly different from that recorded at the same time during hypotension-free sessions (-13.9% +/- 6.4% versus -12.7% +/- 5.2%; P = 0.149). Group, baseline plasma-dialysate sodium gradient, RBV line irregularity, and early RBV and HR reduction during dialysis influenced the relative risk for symptomatic hypotension with a sensitivity of 80% versus 30% for RBV alone.We found no difference in reduction in RBV in the three groups and no critical RBV level for the appearance of symptomatic hypotension. With variables easily available within 40 minutes of dialysis, RBV monitoring increases the prediction of symptomatic hypotension.

A 10-year follow-up of a randomized study with methylprednisolone and chlorambucil in membranous nephropathy. The natural course of idiopathic membranous nephropathy is variable, with some patients slowly progressing to renal failure while others maintain normal renal function over the entire time. Whether to treat this disease or not is controversial due to the lack of controlled data about the long-term effects of treatment. We updated at 10 years the results of a controlled trial in which 81 patients with idiopathic membranous nephropathy and nephrotic syndrome were randomly assigned to receive symptomatic therapy (39 patients) or a treatment of six months with methylprednisolone and chlorambucil (42 patients). The probability of surviving without developing end-stage renal disease at 10 years was 92% in patients given methylprednisolone and chlorambucil versus 60% in controls (P = 0.0038). The slope of the reciprocal of plasma creatinine up to 10 years was significantly better in treated patients than in controls (P = 0.035). The probability of having a complete or partial remission of the nephrotic syndrome was significantly higher in treated patients (P = 0.000). Patients assigned to therapy spent significantly longer time without nephrotic syndrome than untreated patients (P = 0.0001). Four patients had to stop treatment because of reversible side-effects. In the long-term one treated patient developed diabetes and another one became obese. In conclusion, a six-month therapy with methylprednisolone and chlorambucil increases the probability of remission of proteinuria and protects from renal function deterioration even in the long-term. This treatment may avoid dialysis or death within 10 years to about one third of nephrotic patients with membranous nephropathy.

The aim of this study was to evaluate the role of blood pressure in the progression of chronic renal failure (CRF) in polycystic kidney disease, by analysing the behaviour of 74 affected patients, out of 456 CRF patients with various underlying nephropathies enrolled in a multicentre, formal prospective trial aimed at clarifying the role of protein restriction in retarding CRF progression. Because no difference was found between the patients on a low protein and those on a controlled protein diet, an inductive analysis was made by separating all of the patients into fast progressive or slowly progressive CRF groups. Hypertensive patients were defined as those with a mean resting blood pressure of more than 107 mmHg; of the 62 polycystic patients who completed the study or who reached an end point, 41 patients were hypertensive and 21 normotensive (10 of whom were pharmacologically controlled). The results of the stratified analysis, taking into account the degree of renal function deterioration and the underlying disease, showed a significant relationship between hypertension and CRF progression only in patients with polycystic kidney disease.

Four patients, stable on acetate hemodialysis (AHD), were switched to acetate-free biofiltration (AFB) which differs from AHD and bicarbonate hemodialysis (BHD) in that the dialysate contains no buffer, which is given intravenously as a hypertonic (1/6 M) Na bicarbonate solution. Within the 1st month the patients developed thirst and hypertension attributed to a positive Na balance. The aim of this investigation was to check this (1) by a study based on the predictable changes induced in the body compartments of 13 patients by the infusion and ultrafiltration (UF) of a hypertonic solution and (2) by direct determination and calculation of 28 Na mass balances in BHD and AFB. The theoretical model indicated that infusion of 4.87 liters of a 166.7 mEq/l Na bicarbonate solution and UF of the same amount caused a positive balance of 233 mosm of Na. The Na mass balances showed a relationship between Na transmembrane gradient and loss or gain of Na in both methods (p less than 0.0001). The slopes of the regression lines were not significantly different but there was a highly significant difference between the y axis intercepts (p less than 0.0001), which indicates that the same Na transmembrane gradient that gives no net change of Na in BHD, induces a net gain of 240 mosm (120 mEq of Na) in AFB and that to obtain the same Na balance dialysate Na should be reduced by about 8 mEq/l in AFB. These data are the same as the theoretical forecast which could be extended to all hemodiafiltration methods in which solutions of any tonicity have to be infused, in order to correctly predict the Na balance.

127 randomly selected patients on haemodialysis showed a high prevalence of ventricular arrhythmias, the frequency of which rose significantly during and after dialysis. These patients have now been followed up for 4 years. Only age and ischaemic heart disease correlated independently with mortality. Although ventricular arrhythmias are often associated with cardiac disease in patients on chronic haemodialysis, they do not seem to predict overall mortality.

We conducted a controlled trial to investigate the long-term effects of treatment with methylprednisolone and chlorambucil in patients with idiopathic membranous nephropathy. We have previously reported that after a mean of 31 months, treated patients did better. We now report the results of a longer follow-up. Eighty-one patients with proteinuria (greater than or equal to 3.5 g per day) and biopsy-proved membranous nephropathy were randomly assigned to receive either supportive therapy alone or a six-month course of corticosteroids alternated with chlorambucil (0.2 mg per kilogram of body weight per day) every other month. Methylprednisolone was first given intravenously in three pulses (1 g per day) and was then given orally (0.4 mg per kilogram per day) for 27 days. The patients were followed for 2 to 11 years (median, 5). Two patients in the control group and one in the treatment group died. At the last follow-up visit, 9 of 39 patients assigned to the control group (23 percent) and 28 of 42 patients assigned to the treatment group (67 percent) did not have the nephrotic syndrome. At five years there were more remissions of the nephrotic syndrome in treated patients than in controls (22 of 30 vs. 10 of 25; P = 0.026). Compared with base-line values, the mean reciprocal of the plasma creatinine level declined significantly in the control group (33 percent; P = 0.0002) but not in the treatment group (6 percent; P not significant). Plasma creatinine increased by 50 percent or more in 19 controls (49 percent) and in 4 treated patients (10 percent). We conclude that a six-month course of methylprednisolone and chlorambucil can bring about sustained remission of the nephrotic syndrome and help to preserve renal function in patients with idiopathic membranous nephropathy.

Five cases of acute post-partum renal failure with microangiopathic haemolytic anaemia are reported. In 4 patients the pregnancy had been complicated by preeclampsia or frank eclampsia, and in 1 patie

Effects of different membranes and dialysis technologies on patient treatment tolerance and nutritional parameters. There is increasing evidence that the biochemical and cellular phenomena induced by blood/membrane/dialysate interactions contribute to dialysis-related intradialytic and long-term complications. However, there is a lack of large, prospective, randomized trials comparing biocompatible and bioincompatible membranes, and convective and diffusive treatment modalities. The primary aim of this prospective, randomized trial was to evaluate whether the use of polysulfone membrane with bicarbonate dialysate offers any advantages (in terms of treatment tolerance, nutritional parameters and pre-treatment β 2 -microglobulin levels) over a traditional membrane (Cuprophan®). A secondary aim was to assess whether the use of more sophisticated methods consisting of a biocompatible synthetic membrane with different hydraulic permeability at different ultrafiltration rate (highflux hemodialysis and hemodiafiltration) offers any further advantages. Seventy-one Centers were involved and stratified according to the availability of only the first two or all four of the following techniques: Cuprophan® hemodialysis (Cu-HD), low-flux polysulfone hemodialysis (LfPS-HD), high-flux polysulfone high-flux hemodialysis (HfPS-HD), and high-flux polysulfone hemodiafiltration (HfPS-HDF). The 380 eligible patients were randomized to one of the two or four treatments (132 to Cu-HD, 147 to LfPS-HD, 51 to HfPS-HD and 50 to HfPS-HDF). The follow-up was 24 months. No statistical difference was observed in the algebraic sum of the end points between bicarbonate dialysis with Cuprophan® or with low-flux polysulfone, or among the four dialysis methods under evaluation. There was a significant decrease in pre-dialysis plasma β 2 -microglobulin levels in high-flux dialysis of 9.04 ± 10.46 mg/liter (23%) and in hemodiafiltration of 6.35 ± 12.28 mg/liter (16%), both using high-flux polysulfone membrane in comparison with Cuprophan® and low-flux polysulfone membranes (P = 0.032). The significant decrease in pre-dialysis plasma β 2 -microglobulin levels could have a clinical impact when one considers that β 2 -microglobulin accumulation and amyloidosis are important long-term dialysis-related complications.

A new case of acute renal failure after rifampicin is presented, together with a review of the 36 similar cases published up to date in the literature. Evidence is provided that irregularities in drug intake, either as true intermittent treatment or as discontinuation of continuous therapy, play an important role in the pathogenesis of such reactions. Renal failure appeared after a rather long uneventful interval from the beginning of rifampicin therapy, ranging from 1 month to more than 1 year. Its clinical course was favourable in all but one case; the histological picture was mainly of tubulo-interstitial type. The controversial immunological data reported in the literature are reviewed; an increase of histamine release by rat mast cells has been found in presence of rifampicin plus the serum of our patient: the implications of this finding are discussed, suggesting a possible immunological factor in the pathogenesis of acute renal failure after rifampicin.

1. Blood pressure, plasma renin concentration, exchangeable body sodium, plasma volume and extracellular fluid volume were measured in five patients on maintenance haemodialysis for end-stage renal disease in whom hypertension was relatively easy to control by the combination of dialysis and restriction of salt intake. Measurements were made on three occasions: on a free salt intake the day before dialysis; on a low salt intake the day after dialysis; on a free salt intake the day before dialysis after nephrectomy. 2. The fall of blood pressure after haemodialysis and salt intake restriction was accompanied by a decrease of exchangeable body sodium and body fluids while plasma renin concentration increased. The fall of blood pressure after bilateral nephrectomy was accompanied by a fourfold decrease of plasma renin without any change of the other variables. 3. The hypertension of these patients might thus be considered ‘salt and water dependent’ or ‘renin dependent’ according to the means used to decrease blood pressure.

There is general agreement that hypertension is a prognostic index of the progression of chronic renal insufficiency (CRI), although it remains to be clarified whether this is related to the hypertension per se, or to the underlying disease and the level of CRI. In an attempt to clarify this important point, an inductive analysis was made of the behavior of blood pressure values and their relationship to the progression of CRI in 456 patients (pts) who participated in a multicenter prospective formal randomized trial, designed to compare the effects of a restricted and a controlled protein diet on CRI progression. An analysis was also made (on the population as a whole and by separating the pts into fast progressive and slowly progressive groups) of the type and frequency of the anthypertensive drugs used, the number and type of drugs used in association, and their possible relationship to the progression of CRI. Of the 456 enrolled pts, 406 (89%) were defined as hypertensive at entry (mean blood pressure > 107 mm Hg); 324 out of the 380 pts (85.3%) who completed the 24-month follow-up or reached an end point were treated with anthypertensive drugs. There was a significant difference at entry between the supine blood pressure values of the pts with fast progressive CRI (182 pts), and those of the pts with slowly progressive CRI (198 pts). During the follow-up period, no significant differences were observed between the two groups. There was no difference in the blood pressure levels reached with the different drugs used. The results of our trial seem to give some support to the idea that hypertension may affect the progression of CRI, but the hypothesis that a reduction in blood pressure levels leads to a slowing down in the progression of CRI remains to be clarified.

An AutoRegressive (AR) model spectral estimation is employed in the study of the Heart Rate Variability (HRV) signal obtained during hemodialytic (HD) treatments characterized by the presence of numerous cardiac arrhythmias. The AR spectral estimation is implemented in a such a way to reduce the impact of ectopic beats on the analysis of HRV signal. The spectral parameters (LF, HF powers, LF/HF ratio), which are able to quantify the sympatho-vagal balance in the setting of heart rate values, are estimated by means of a batch spectral analysis with the aim to extract more information about the mechanisms regulating cardiac frequency during HD sessions.

In order to evaluate the prognostic factors concerning the rate of progressive deterioration of renal function, we made an inductive analysis of the behaviour of 456 patients in a multicentre, formal prospective trial aimed at clarifying the possible role of protein restriction in retarding the progression of chronic renal insufficiency (CRI). The main clinical and laboratory findings in patients whose plasma creatinine (PCr) levels doubled in comparison with baseline randomization values or who needed dialysis within 24 months after onset of the study were compared with those of the other patients. In addition, independently of the assigned diet, we tested the main variables that might affect CRI progression (sex, systolic and diastolic blood pressure, change in body weight, hematocrit, calcium-phosphate product, proteinuria, protein catabolic rate, total cholesterol and triglycerides). We used multiple regression analyses and also plotted the mean values of these parameters in each patient against an estimate of the deterioration of chronic renal failure based on the difference between the final and the initial reciprocal of the PCr and the creatinine clearance (CCr) levels. A descriptive analysis of the behaviour of PCr in the three CRI groups and in the four underlying diseases groups was made. PCr levels at entry, underlying disease and proteinuria were prognostic factors for CRI progression. The increase in PCr was 0.0102 mg/dl/month in patients with nephrosclerosis, 0.0203 mg/dl/month in interstitial nephropathy, 0.0360 mg/dl/month in glomerulonephritis and 0.0704 mg/dl/month in polycystic kidney disease.(ABSTRACT TRUNCATED AT 250 WORDS)