Residual renal function and dialysis modality: Is it really beneficial to preserve residual renal function in dialysis patients? (Review Article)

Objectively measured and self-reported nonadherence among Jordanian patients receiving hemodialysis

This study assessed nonadherence behavior to diet and fluid restrictions and examined the association between nonadherence behavior and demographic and clinical characteristics among Jordanian adults with end-stage renal disease receiving hemodialysis. A descriptive, correlational, cross-sectional design was used. The patients were interviewed within the first 90 minutes of dialysis session using the Dialysis Dietary and Fluid Nonadherence questionnaire (DDFQ). Demographic and clinical data were gathered from the patients and the medical records. The objective markers of dietary and fluid nonadherence (potassium, phosphorus, blood urea nitrogen, and interdialytic weight gain) were followed for the last 3 months, and average values were calculated. Diet and fluid nonadherence was common among Jordanian hemodialysis patients as 17-80% were nonadherent using different measures. Significant strong associations were found between the DDFQ subscales, and significant moderate associations between DDFQ and objective markers of dietary and fluid nonadherence. Youth, male gender, smokers, prolonged dialysis vintage, and less residual renal function were associated with nonadherence regardless of the measures used. There was substantial consistency between the DDFQ and objective measures of dietary and fluid nonadherence among Jordanian adults with end-stage renal disease receiving hemodialysis. Future interventional research should incorporate DDFQ and objective markers to measure dietary and fluid nonadherence and health-related outcomes.

Early start of dialysis: a critical review

In the US, patients who initiate dialysis "early" (at Modification of Diet in Renal Disease estimated GFR [eGFR]> 10 ml/min per 1.73 m(2)) account for over 50 percent of new dialysis starts. This trend to an early start is based on conventional wisdoms regarding benefits of dialytic clearance, that albumin levels are nutritional markers, and early dialytic therapy is justified to improve nutrition especially in diabetics and that waiting until low levels of eGFR (i.e., <6 ml/min per 1.73 m(2)) may be dangerous. In order to justify early dialysis treatment, the therapy must provide a morbidity, mortality, or quality of life benefit. The current review examines whether early dialysis initiation provides any of these benefits and whether the conventional wisdoms that have promoted this early dialysis trend are valid. Utilizing this information and the results of recent large observational studies and the randomized controlled Initiating Dialysis Early and Late (IDEAL) study, we suggest that dialysis initiation is justified at GFR levels of 5-9 ml/min/1.73 m(2), if accompanied by uremia symptoms or fluid management issues.

Equivalent continuous clearances EKR and stdK in incremental haemodialysis

BACKGROUND

Many haemodialysis patients have residual renal function (RRF), which as such is insufficient to maintain satisfactory quality of life but reduces the demands of treatment and improves outcomes. In incremental dialysis, the dose is adjusted according to RRF, but how should it be done?

METHODS

Urea generation rate (G) and distribution volume (V) were determined by the double-pool urea kinetic model in 225 haemodialysis sessions of 30 patients. The effect of different degrees of RRF on equivalent renal urea clearance (EKR), standard urea clearance (stdK) and urea concentrations and required treatment times to achieve the HEMO study standard dose equivalent EKR and stdK targets were studied by computer simulations.

RESULTS

Ignoring RRF leads to underestimation of EKR, stdK, urea generation rate and protein equivalent of nitrogen appearance. Both EKR and stdK increase linearly with renal urea clearance (Kr). The HEMO standard dose equivalent EKRc is 13.8 mL/min/40 L and stdK/V 2.29 /wk (9.1 mL/min/40 L). The required treatment time to achieve the HEMO-equivalent targets has an almost linear inverse relationship to Kr. If the HEMO standard dose equivalent EKR or stdK is used as the target, RRF may replace several hours of weekly dialysis treatment time. stdK appreciates RRF more than EKR.

CONCLUSIONS

RRF is included in the original EKR and stdK concepts. EKR and stdK--determined by kinetic modelling--are promising measures of adequacy in incremental dialysis.

Hemodialysis versus peritoneal dialysis: a case control study of survival in patients with chronic kidney disease stage 5

It is still controversial whether the mode of dialysis or preexisting comorbidities may influence the prognosis of patients with chronic kidney disease stage 5. Therefore, we performed a prospective case control study to evaluate whether the mode of dialysis may influence outcome. We found 25 cases on peritoneal dialysis (PD) treatment and 75 age and sex-matched controls on hemodialysis (HD) treatment for more than 3 months. Analysis was by intention-to-treat. During the follow up of 58 months, 6 out of 25 patients (24%) died in the PD group, whereas in the HD group 26 out of 75 patients (35%) died (relative risk 0.69 [95% CI 0.32 to 1.49]; P = 0.46). Survival was not significantly different between the groups as indicated by Mantel-Cox log-rank test (hazard ratio 0.52 [95% CI 0.25 to 1.10]; P = 0.11). Multiple variable regression showed that age and diabetes mellitus, but not mode of dialysis, predicted death in patients with chronic kidney disease. It is concluded that age and comorbidities but not mode of dialysis are important to predict survival in patients with chronic kidney disease stage 5.

Comparison of residual renal function in patients undergoing twice-weekly versus three-times-weekly haemodialysis

AIM

Patients with end-stage renal disease (ESRD) often start long-term haemodialysis (HD) thrice weekly, regardless of the level of residual renal function (RRF). In this study, we investigated whether ESRD patients having sufficient RRF can be maintained on twice-weekly HD, and how they fare compared to patients without RRF on thrice-weekly HD.

METHODS

We analyzed 74 patients who had undergone long-term HD and maintained on the same dialysis frequency from February 1998 to July 2005, and followed until December 2005. We compared the clinical variables between twice-weekly and thrice-weekly HD patients and a second analysis testing the residual urine output as an independent predictor for twice-weekly HD.

RESULTS

After a mean follow up of 18 months, twice-weekly HD patients (n = 23) had lower serum beta2-microglobulin than thrice-weekly HD patients (n = 51). Moreover, the twice-weekly group had a slower decline of RRF, as indicated by their higher urine output and creatinine clearance, fewer intradialytic hypotensive episodes, and required less frequent hospitalization. There was no difference between the two groups in cardiothoracic ratio or indices of nutrition and inflammation. Multivariable logistic regression identified age (odds ratio (OR), 1.866; 95% CI, 1.093-3.183), dry body mass index (OR, 0.790; 95% CI, 0.625-0.999), and urine output (OR, 1.093; 95% CI, 1.026-1.164) as predictors for maintaining twice-weekly HD.

CONCLUSION

Our data suggest that when patients who have sufficient urine output are given twice-weekly HD, they maintain dialysis adequacy and exhibit better preservation of RRF than patients on thrice-weekly HD.

In vitro utilization of ferromagnetic nanoparticles in hemodialysis therapy

The in vitro utilization of biocompatible ferromagnetic nanoparticles (BFNs) in hemodialysis (HD), routinely used today for the treatment of end stage renal disease (ESRD), is introduced in this work. The proposed strategy is termed magnetically assisted hemodialysis (MAHD) and it aims to become a more efficient development of conventional HD. The method is based on the production of biocompatible ferromagnetic nanoparticles-targeted binding substances conjugates (BFNs-TBSs Cs) constructed of BFNs and specifically designed TBSs that should have high affinity and binding capacity for target toxic substances (TTSs) which must be removed from the ESRD patient subjected to HD. Antibodies or even specific proteins could serve as the TBS of the desired BFNs-TBSs Cs. The BFNs-TBSs Cs should be administered to the patient timely prior to the MAHD session so as to bind with the desired TTSs during their free circulation in the vascular network. Eventually, the complete BFNs-TBSs-TTSs structure can be selectively removed during the MAHD session by means of an external inhomogeneous magnetic field that is applied either at the dialyzer or at other collection point(s) along the blood circulation line of the dialysis machine. The advantages of MAHD over conventional HD regarding the patient's comfort and overall health status are discussed in detail among practical issues. To examine this proposition we employed Fe(3)O(4) and bovine serum albumin (BSA) as the BFN and the TBS constituents respectively, since they are both highly biocompatible. By means of x-ray diffraction, atomic force microscopy, circular dichroism spectropolarimetry, UV-vis spectrophotometry, SQUID magnetometry, and nuclear magnetic resonance we evaluated (i) the structural/morphological characteristics, (ii) the magnetic retraction efficiency, and most importantly (iii) the toxin binding affinity and capacity of both bare Fe(3)O(4) BFNs and Fe(3)O(4)-BSA Cs by performing in vitro experiments on specific TTSs. Homocysteine and p-cresol were chosen as representative TTSs and were investigated in great detail. The results obtained prove the in vitro applicability of the proposed MAHD method. Corrections were made to this article on 6 November 2007 (see figure 10 caption and lines 10 and 11 of page 11). The corrected electronic version is identical to the print version.

Combining dialysate and blood recirculation to boost uremic toxin removal: theory and simulation study

Emerging concepts in renal replacement therapies such as daily hemodialysis (HD) and wearable artificial kidney (WAK) meet the challenges derived from the aging of renal disease population. The successful results of blood recirculation to improve the dialysis clearance of medium-high uremic toxins suggest that this technique could be used both in daily HD and WAK. However, blood recirculation induces a reduction of small solutes clearance. This work analyzes the ability of a nonregenerated recirculating dialysate technique to avoid that reduction. The study uses in silico simulations with in vitro data from several commercial dialyzers and very compact dialyzer models derived from them. The resulting combined optimization system (recirculating blood-dialysate system [RBDS]) reached low solute dialysance improvements above 100% in different scenarios. Our outcomes show the RBDS performs best with very compact dialyzers, in agreement with the requirements of daily HD and WAK.

Is it time to revisit residual renal function in haemodialysis? (Review Article)

Residual renal function (RRF) is not currently emphasized for patients undergoing haemodialysis (HD). The role of RRF is well recognized in the peritoneal dialysis population as studies have clearly demonstrated a survival benefit with preservation of RRF. There is however, data to suggest that RRF is important in HD patients as well. Contemporary HD therapies using high flux biocompatible synthetic dialysers, bicarbonate buffered ultrapure dialysis fluids with ultrafiltration control appear to allow better preservation of RRF. The long held belief that peritoneal dialysis is better at preserving RRF than HD may no longer be true. More robust studies are required to determine the relative importance of RRF in HD and strategies to best preserve this vital asset.