The incremental treatment of ESRD: a low-protein diet combined with weekly hemodialysis may be beneficial for selected patients.

BACKGROUND: Infrequent dialysis, namely once-a-week session combined with very low-protein, low-phosphorus diet supplemented with ketoacids was reported as a useful treatment schedule for ESRD patients with markedly reduced residual renal function but preserved urine output. This study reports our findings from the application of a weekly dialysis schedule plus less severe protein restriction (standard low-protein low-phosphorus diet) in stage 5 CKD patients with consistent dietary discipline. METHODS: This is a multicenter, prospective controlled study, including 68 incident CKD patients followed in a pre-dialysis clinic with Glomerular Filtration Rate 5 to 10 ml/min/1.73/ m2 who became unstable on the only medical treatment. They were offered to begin a Combined Diet Dialysis Program (CDDP) or a standard thrice-a-week hemodialysis (THD): 38 patients joined the CDDP, whereas 30 patients chose THD. Patients were studied at baseline, 6 and 12 months; hospitalization and survival rate were followed-up for 24 months. RESULTS: Volume output and residual renal function were maintained in the CDDP Group while those features dropped quickly in THD Group. Throughout the study, CDDP patients had a lower erythropoietin resistance index, lower ß2 microglobulin levels and lower need for cinacalcet of phosphate binders than THD, and stable parameters of nutritional status. At 24 month follow-up, 39.4% of patients were still on CDDP; survival rates were 94.7% and 86.8% for CDDP and THD patients, respectively, but hospitalization rate was much higher in THD than in CDDP patients. The cost per patient per year resulted significantly lower in CDDP than in THD Group. CONCLUSIONS: This study shows that a CDDP served to protect the residual renal function, to maintain urine volume output and to preserve a good nutritional status. CDDP also blunted the rapid ß2 microglobulin increase and resulted in better control of anemia and calcium-phosphate abnormalities. CDDP was also associated with a lower hospitalization rate and reduced need of erythropoietin, as well as of drugs used for treatment of calcium-phosphate abnormalities, thus leading to a significant cost-saving. We concluded that in selected ESRD patients with preserved urine output attitude to protein restriction, CDDP may be a beneficial choice for an incremental hemodialysis program.

Phosphate levels in patients treated with low-flux haemodialysis, pre-dilution haemofiltration and haemodiafiltration: post hoc analysis of a multicentre, randomized and controlled trial.

BACKGROUND: Whether convective therapies allow better control of serum phosphate (P) is still undefined, and no data are available concerning on-line haemofiltration (HF). The objectives of the study are to evaluate the effect of convective treatments (CTs) on P levels in comparison with low-flux haemodialysis (HD) and to evaluate the correlates of serum phosphate in a post hoc analysis of a randomized clinical trial. METHODS: This analysis was performed in the database of a multicentre, open label and randomized controlled study in which 146 chronic HD patients from 27 Italian centres were randomly assigned to HD (70 patients) or CTs: on-line pre-dilution HF (36 patients) or on-line pre-dilution haemodiafiltration (40 patients). RESULTS: CTs did not affect P (P = 0.526), calcium (Ca) (P = 0.849) and parathyroid hormone levels (P = 0.622). P levels were associated with the use of phosphate binders including aluminium-based phosphate binders (P < 0.001) and sevelamer (P < 0.001), pre-dialysis bicarbonate levels (P < 0.001) and pre-dialysis blood K levels (P < 0.001). On multivariate analysis (generalized linear model), serum P was again largely unassociated with CTs (P = 0.631). Notably, participating centres were by far the strongest independent correlate of serum P, explaining 45.3% of the variance of serum P over the trial and this association was confirmed at multivariate analysis. Bicarbonate (P < 0.001) and, to a weaker extent, serum K (P = 0.032) were independently related to serum P. CONCLUSIONS: In comparison with low-flux HD, CTs did not significantly affect serum P levels. Participating centres were the main source of P variability during the trial followed by treatment with phosphate binders, serum bicarbonate and, to a weak extent, serum potassium levels (ClinicalTrials.gov Identifier: NCT011583309).

[Clinical results of convective therapies]. / Risultati clinici delle terapie convettive secondo l'EBM.

Convective therapies can be a good additional option in extracorporeal renal replacement therapy, but so far the clinical evidence in their favor is rather scarce. In this review the results of the most important studies are discussed, grouped by main outcomes: intradialytic cardiovascular stability, beta2-microglobulin, mortality, calcium-phosphorus metabolism, and possible effect on anemia. In general, the use of convective therapies for reimbursement reasons but without any clear clinical benefit is not justified. The fractional division of convective therapies into various subtypes and the use of different levels of convection among centers make their widespread clinical implementation unlikely in the near future. No firm conclusions can be drawn right now and more controlled clinical trials on convective therapies will be needed to clarify their role in renal replacement therapy.

[Pre- and postdilution hemofiltration]. / Emofiltrazione in pre- e in post-diluizione.

Hemofiltration is a dialysis technique based on uremic toxin removal by convection only. It can significantly increase the removal of high-molecularweight solutes. The introduction of online technology has contributed to the widespread use of this technique at a reduced cost. The clinical benefits are improved cardiovascular stability and better efficiency of ß2-microglobulin removal with reduction of uremic amyloidosis. Moreover, hemofiltration is the method of choice for continuous therapy in critically ill patients. Its limitation is the low removal of small molecules, which depends on the ultrafiltrate volume. Reinfusion to replace the large volume of ultrafiltrate produced during hemofiltration can be done in postdilution or predilution mode. The latter ensures better flow conditions and better urea clearance. For this reason intermittent hemofiltration in predilution mode is generally the most used technique.

Predictors of haemoglobin levels and resistance to erythropoiesis-stimulating agents in patients treated with low-flux haemodialysis, haemofiltration and haemodiafiltration: results of a multicentre randomized and controlled trial.

BACKGROUND: Predictors of haemoglobin (Hb) levels and resistance to erythropoiesis-stimulating agents (ESAs) in dialysis patients have not yet been clearly defined. Some mainly uncontrolled studies suggest that online haemodiafiltration (HDF) may have a beneficial effect on Hb, whereas no data are available concerning online haemofiltration (HF). The objectives of this study were to evaluate the effects of convective treatments (CTs) on Hb levels and ESA resistance in comparison with low-flux haemodialysis (HD) and to evaluate the predictors of these outcomes. METHODS: Primary multivariate analysis was made of a pre-specified secondary outcome of a multicentre, open-label, randomized controlled study in which 146 chronic HD patients from 27 Italian centres were randomly assigned to HD (70 patients) or CTs: online pre-dilution HF (36 patients) or online pre-dilution HDF (40 patients). RESULTS: CTs did not affect Hb levels (P = 0.596) or ESA resistance (P = 0.984). Hb correlated with polycystic kidney disease (P = 0.001), C-reactive protein (P = 0.025), ferritin (P = 0.018), ESA dose (P < 0.001) and total cholesterol (P = 0.021). The participating centres were the main source of Hb variability (partial eta(2) 0.313, P < 0.001). ESA resistance directly correlated with serum ferritin (P = 0.030) and beta2 microglobulin (P = 0.065); participating centres were again a major source of variance (partial eta(2) 0.367, P < 0.001). Transferrin saturation did not predict either outcome variables (P = 0.277 and P = 0.170). CONCLUSIONS: In comparison with low-flux HD, CTs did not significantly improve Hb levels or ESA resistance. The main sources of variability were participating centres, ESA dose and the underlying disease.

Hemofiltration and hemodiafiltration reduce intradialytic hypotension in ESRD.

Symptomatic intradialytic hypotension is a common complication of hemodialysis (HD). The application of convective therapies to the outpatient setting may improve outcomes, including intradialytic hypotension. In this multicenter, open-label, randomized controlled study, we randomly assigned 146 long-term dialysis patients to HD (n = 70), online predilution hemofiltration (HF; n = 36), or online predilution hemodiafiltration (HDF; n = 40). The primary end point was the frequency of intradialytic symptomatic hypotension (ISH). Compared with the run-in period, the frequency of sessions with ISH during the evaluation period increased for HD (7.1 to 7.9%) and decreased for both HF (9.8 to 8.0%) and HDF (10.6 to 5.2%) (P < 0.001). Mean predialysis systolic BP increased by 4.2 mmHg among those who were assigned to HDF compared with decreases of 0.6 and 1.8 mmHg among those who were assigned to HD and HF, respectively (P = 0.038). Multivariate logistic regression demonstrated significant risk reductions in ISH for both HF (odds ratio 0.69; 95% confidence interval 0.51 to 0.92) and HDF (odds ratio 0.46, 95% confidence interval 0.33 to 0.63). There was a trend toward higher dropout for those who were assigned to HF (P = 0.107). In conclusion, compared with conventional HD, convective therapies (HDF and HF) reduce ISH in long-term dialysis patients.

Comparison between hemofiltration and hemodiafiltration in a long-term prospective cross-over study.

BACKGROUND: The objective of the study was to compare the convective treatment modes, on-line hemofiltration (HF) and on-line hemodiafiltration (HDF), regarding cardiovascular tolerance and effects on blood pressure, when applied under similar conditions in stable dialysis patients. METHODS: 39 clinically stable dialysis patients were treated with HD for 6 months (run-in period), followed by HF and HDF in random order for 2x6 months. Similar biocompatibility (same membrane and fluid quality), similar treatment time and urea Kt/V were achieved using AK100/200 ULTRA machines, polyamide membranes in low-flux and high-flux versions and appropriate adjustment of blood flow rate (Qb) and dilution ratio (Qb/Qinf). Predilution was used for HDF (target dilution ratio = 2/1 ) as well as for HF (target dilution ratio = 1/1). RESULTS: 30 patients completed the study; 5 dropped out for non-study related reasons and 4 for non-compliance. Treatment with HF in comparison to HDF showed fewer hypotension episodes during the sessions per patient and month (HF: 0.5, HDF 1.1; p = 0.017), less plasma expander administration per patient and month (HF: 35.9 ml, HDF: 103.1 ml; p = 0.035), fewer episodes of intra-session headache (HF: 0.1, HDF: 0.4; p = 0.06), and higher pre-session MAP (HF: 98.4 mmHg, HDF: 93.8 mmHg; p = 0.037). No significant difference was found in inter-treatment weight gain, post-session MAP, or pre-session plasma sodium. CONCLUSIONS: HF and HDF provide good control of intra-session symptoms and blood pressure in stable patients. Treatment with HF resulted in a significant reduction in intra-session hypotension and a slight but significant increase in pre-session MAP, caused by an increase in systolic BP without any effect on the prevalence of hypertension or the dose of antihypertensive drugs, all compared to HDF.

Convection versus diffusion in dialysis: an Italian prospective multicentre study.

The concept of dialysis adequacy has to be widened to include medium size and large molecule removal in addition to urea kinetics. The HEMO study found a non-significant trend toward a beneficial effect on mortality of high-flux dialysis compared with low-flux dialysis. In that study, the beneficial effect of convection could have been attenuated by the fact that 'internal filtration' in high-flux haemodialysis (HD) is lower than that expected by convection in haemofiltration (HF) or haemodiafiltration (HDF). To explore the putative beneficial effect of convection, this Italian multicentre study was planned, comparing on-line convective treatments (HF and HDF) with standard, low-flux HD. The enrolled patients will be evaluated prospectively on their usual treatment for 2 months (baseline period) and subsequently randomized to continue either with low-flux HD (50%) or to start on-line convective treatment (50%), HF or HDF according to a 1:1 ratio. The primary end point of the study will be cardiovascular stability and blood pressure control. As secondary aims of the study, the impact on symptoms, morbidity and mortality will be assessed. Feasibility and patient compliance during HF and HDF treatments will also be evaluated. The experimental phase of the study, of at least 2 years, is divided into a 3-month adaptation period and a subsequent evaluation period. A recruitment period of 1 year is planned. The study design has adequate power to detect an absolute reduction of 3% hypotensive episodes with the experimental convective treatments compared with standard low-flux HD.

Immunosuppressive treatment in dialysis patients.

Immunosuppressive treatment is a critical procedure in dialysis patients, in whom an increased risk of infection is already present. Haemodialytic treatment increases the patient's susceptibility to bacterial infection, mainly by impairing polymorphonuclear leukocyte phagocytosis, but it can also restore the patient's immunological defences by improving the T-cell function, which is reduced by pre-dialysis uraemia. Patients on dialysis usually continue the immunosuppressive treatment that had been established for the illness that caused their renal failure [e.g. systemic lupus erythematosus (SLE) or renal vasculitis]. Less frequently, patients on dialysis need immunosuppression for immunological or inflammatory diseases that appear 'de novo' after initiation of dialysis. SLE and antineutrophil cytoplasmic antibody (ANCA)-related vasculitides are immunological illnesses that frequently cause end-stage renal failure (ESRF). A reduction in serological and/or clinical activity is usually observed in SLE patients after they reach ESRF, but a similar or increased frequency of extrarenal relapse episodes in lupus patients after the beginning of the dialysis, compared with the pre-dialysis period, has also been described. Frequency of relapse episodes in patients on dialysis treatment for ANCA-related vasculitides varies from 10 to 30% per patient/year in different reports, and it is higher than the frequency of relapses after renal transplantation; anti-rejection therapy seems to be the most likely protective factor in these conditions. The treatment of relapse episodes in SLE or ANCA vasculitis in dialysis-dependent patients is usually not different from treatment of relapses in patients with dialysis-independent renal function. However, the risk of severe infection caused by immunosuppressive treatment is relevantly higher in dialysis patients. Furthermore, there is a lack of prospective controlled studies indicating the optimal management of immunosuppressive protocols in dialysis patients. A particularly careful assessment of the patient's risks and benefits is necessary in deciding how long immunosuppressive treatment should last after acute or rapidly progressive renal damage, that should require dialysis treatment, in patients with SLE or ANCA vasculitis. In the above conditions, the risks of prolonging immunosuppressive treatment must be balanced against the relatively good prognosis offered to these patients by dialysis and renal transplantation. In a retrospective review of 24 patients receiving long-term steroid therapy (>3 months) in our dialysis unit in the past 5 years, we found relevant clinical differences in the patients receiving steroid treatment compared with 24 controls. Steroid-treated patients showed less favourable nutritional conditions, with lower serum albumin and body mass index vs non-steroid-treated patients; moreover, C-reactive protein values were persistently higher in the steroid-treated group. Steroid treatment in these patients was usually performed at the beginning of regular dialysis, as a continuation of the treatment that started before the initiation of dialysis. Only two patients, who needed a prolonged low-dose steroidal treatment to control a malnutrition-inflammation-atherosclerosis (MIA) syndrome, started steroids many years after beginning dialysis. Steroid treatment was effective in improving the nutritional condition and inflammatory symptoms in these two patients after all conventional measures had failed.