Treatment time, chronic inflammation, and hemodynamic stability: the overlooked parameters in hemodialysis quantification

Estimated Glomerular Filtration Rate in Chronic Kidney Disease: A Critical Review of Estimate-Based Predictions of Individual Outcomes in Kidney Disease

Chronic kidney disease (CKD) is generally regarded as a final common pathway of several renal diseases, often leading to end-stage kidney disease (ESKD) and a need for renal replacement therapy. Estimated GFR (eGFR) has been used to predict this outcome recognizing its robust association with renal disease progression and the eventual need for dialysis in large, mainly cross-sectional epidemiological studies. However, GFR is implicitly limited as follows: (1) GFR reflects only one of the many physiological functions of the kidney; (2) it is dependent on several non-renal factors; (3) it has intrinsic variability that is a function of dietary intake, fluid and cardiovascular status, and blood pressure especially with impaired autoregulation or medication use; (4) it has been shown to change with age with a unique non-linear pattern; and (5) eGFR may not correlate with GFR in certain conditions and disease states. Yet, many clinicians, especially our non-nephrologist colleagues, tend to regard eGFR obtained from a simple laboratory test as both a valid reflection of renal function and a reliable diagnostic tool in establishing the diagnosis of CKD. What is the validity of these beliefs? This review will critically reassess the limitations of such single-focused attention, with a particular focus on inter-individual variability. What does science actually tell us about the usefulness of eGFR in diagnosing CKD?

Subjective global assessment of nutrition, dialysis quality, and the theory of the scientific method in Nephrology practice

In an era of evidence-based medicine and dialysis performance measures, there is strong motivation to find specific, objective, quantifiable, and reproducible parameters to characterize the clinical condition of chronic kidney disease patients and to present population-wide statistics that may describe quality of care in dialysis centers. Yet, in the last three decades, several studies demonstrated that while parameters including Kt/V urea, serum phosphorus, parathyroid hormone, serum cholesterol fulfill all these criteria, efforts to optimize these lab parameters failed to improve survival on dialysis. However, subjective assessments of nutrition including subjective global assessment and malnutrition-inflammation score, while not ideally suited for statistical analysis and not optimal from the point of view of scientific methodology due to their general, semi-quantifiable, subjective nature have, nevertheless, proved themselves as some of the strongest predictors of clinical outcomes in the dialysis population. Where does this paradox leave us? We propose that a deeper understanding of relevance of these variables in the dialysis population may improve appreciation of the clinical situation of individual patients and may result in a paradigm shift from dialysis adequacy to quality dialysis.

The effects of dialysis modality choice on cognitive functions in patients with end-stage renal failure: a systematic review and meta-analysis

INTRODUCTION

Cognitive dysfunction is a major consequence of end-stage renal disease (ESRD) and has further detrimental effects on both functionality and the quality of life for patients. While peritoneal dialysis is generally advocated in ESRD, there is a substantial knowledge gap about the differential effects of chronic dialysis modalities on cognitive dysfunction and decline. The aim of this meta-analysis is to evaluate cognitive function in peritoneal dialysis versus hemodialysis patients.

METHODS

We performed a systematic review in different databases to identify studies that assessed the effect of different dialysis modalities on cognitive functions. Inclusion criteria for our meta-analysis were all studies that compared the effects of peritoneal dialysis on cognitive functions compared to intermittent hemodialysis. The data collected were the name of the first author, journal title, year of publication, country where the study was conducted, number of patients in the peritoneal dialysis and hemodialysis arms and methods of assessment of cognitive functions.

RESULTS

Out of 2769 abstracts reviewed in different databases, 11 papers were included in our meta-analysis. Altogether, 195,774 patients were included in the final analysis. The forest plot analysis of the rate of cognitive impairment in different dialysis modalities showed decreased risk of cognitive impairment in the peritoneal dialysis population compared to hemodialysis patients (relative risk = 0.634, confidence interval ranges from 0.508 to 0.790). There was evidence of significant heterogeneity among studies with p < 0.0001 and I² = 85.5%. The sensitivity analysis limited to studies on patients younger than 65 years of age showed similar results (relative risk = 0.516; 95% confidence intervals: 0.379-0.704).

CONCLUSION

Patients on peritoneal dialysis demonstrated a lower odd of cognitive dysfunction compared to those on hemodialysis. Future prospective studies should assess cognitive decline as a meaningful outcome in dialysis patients.

Sustained low-efficiency diafiltration is superior to hemodialysis in promoting renal function recovery in elderly wasp sting victims with stage III acute kidney injury: a retrospective study

Objective: To study the efficacy and safety of sustained low-efficiency diafiltration (SLEDf) versus hemodialysis (HD) for patients with wasp stings who developed stage III acute kidney injury (AKI).

Methods: We retrospectively analyzed the clinical data of consecutive patients who developed AKI following wasp stings. All eligible patients received renal replacement therapy in combination with hemoperfusion. Thereafter, blood purification therapy and HD were performed with a volumetrically controlled machine and 1.7 m² surface, Fresenius Polysulfone HD filter and SLEDf was undertaken with a volumetrically controlled machine and 1.3 m² surface, Fresenius Polysulfone HD filter.

Results: Forty patients developed stage III AKI following wasp stings, including 14 patients that received SLEDf and 26 patients underwent HD. Thirteen patients were aged less than 60 years and underwent HD (group I), 27 patients were aged at least 60 years, including 13 patients undergoing HD (group II) and 14 patients receiving SLEDf (group III). Groups I and II completed 150 and 162 sessions of HD, respectively, and group III completed 156 sessions of sustained low-efficiency blood purification therapy, including 50 sessions of SLEDf. The time to return to normal serum creatinine levels was 38.8 ± 2.7 days for group I, 47.2 ± 5.3 days for group II, and 39.2 ± 3.3 days for group III. A statistically significant difference was observed in time to normal serum creatinine levels among the three groups.

Conclusion: Elderly wasp victims have more severe illness than younger wasp victims and SLEDf is safe and superior to HD in recovery of renal function of elderly wasp victims.

The association of overhydration with chronic inflammation in chronic maintenance hemodiafiltration patients

INTRODUCTION

Achieving euvolemia is one of the major challenges when treating end-stage renal disease (ESRD) patients receiving maintenance renal replacement therapy. Fluid overload is recognized as an independent predictor of mortality in ESRD, but its association with chronic inflammation is less well explored especially in chronic maintenance hemodiafiltration.

METHODS

We performed a cross-sectional study of 87 prevalent ESRD patients receiving chronic maintenance hemodiafiltration (vintage 66.5 ± 57.1 months) with bioimpedance analysis to characterize the degree of percent overhydration (OH%). We also compared the levels of inflammatory markers, including C-reactive protein (CRP), serum albumin, neutrophil/lymphocyte ratio (NLR), and hemoglobin red cell distribution width (RDW) for the overhydrated (OH% ≥ 15%) versus euvolemic (OH% < 15%) groups. Linear regression analysis was performed to explore relationships between the degree of OH and inflammatory indicators.

FINDINGS

The cohort represented an all-European population with a mean age of 60.9 ± 14.7 years and prevalence of diabetes mellitus of 27%. The entire cohort's OH% was 14.9% ± 5.1% (range -11.1% to 39.0%); further, the <15% group of patients' OH% was 8.0% ± 8.5% versus 20.9% ± 5.1% in the OH% ≥ 15% group (P < 0.0001). Forty-seven patients (53%) were overhydrated by traditional criteria (OH% ≥15%) and 20 patients (23%) were severely overhydrated (OH% > 20%). The euvolemic (OH% <15%) versus severely overhydrated (OH% > 20%) groups had significant differences in markers of inflammation: CRP (9.8 ± 10.6 vs. 21.5 ± 21.6 mg/L, P < 0.006), serum albumin (37.6 ± 02.9 vs. 34.5 ± 5.3 g/L, P < 0.004), and NLR (3.06 ± 1.25 vs. 3.92 ± 2.04; P < 0.004). On linear regression, significant correlations were found between OH% and CRP (r = 0.2899, P < 0.006), serum albumin (r = -0.3670; P < 0.0005), RDW (r = 0.2992; P < 0.005), and NLR (r = 0.2900; P < 0.006).

DISCUSSION

In a prevalent hemodiafiltration cohort, OH was common and correlated with several inflammatory markers.

Peritoneal dialysis: The unique features by compartmental delivery of renal replacement therapy

Despite decades of research, the clinical efficacy of peritoneal dialysis (PD) remains enigmatic. We may wonder why the modality fail in some patients but perhaps the more proper question would be, why it works in so many? We know that the contribution of residual renal function (RRF), more so than in hemodialysis, is critically important to the well-being of many of the patients. Unique features of the modality include the relatively low volume of dialysate fluid needed to provide effective uremic control and the disproportionate tendency for both hypokalemia and hypoalbuminemia, when compared to hemodialysis. It is currently believed that most uremic toxins are generated on the interface of human and bacterial structures in the gastrointestinal tract, the intestinal biota. PD offers disproportionate removal of these toxins upon "first-pass", i.e., via PD fluid exchanges before reaching the systemic circulation beyond the gastrointestinal compartment. Studies examining the net removal gradient of protein-bound uremic toxins during PD are scarce, whereas RRF receives considerably more attention without effective interventions being developed to preserve it. We propose an alternative view on PD, emphasizing the modality's compartmental nature, both for its benefits and the limitations.

When to initiate renal replacement therapy: The trend of dialysis initiation

The timing of renal replacement therapy for patients with end-stage renal disease has been subject to considerable variation. The United States Renal Data System shows an ascending trend of early dialysis initiation until 2010, at which point it decreased slightly for the following 2 years. In the 1990s, nephrologists believed that early initiation of dialysis could improve patient survival. Based on the Canadian-United States Peritoneal Dialysis study, the National Kidney Foundation Dialysis Outcomes Quality Initiative recommended that dialysis should be initiated early. Since 2001, several observational studies and 1 randomized controlled trial have found no beneficial effect when patients were placed on dialysis early. In contrast, they found that an increase in mortality was associated with early dialysis initiation. The most recent dialysis initiation guidelines recommend that dialysis should be initiated at an estimated glomerular filtration rate (eGFR) of greater than or equal to 6 mL/min per 1.73 m(2). Nevertheless, the decision to start dialysis is mainly based on a predefined eGFR value, and no convincing evidence has demonstrated that patients would benefit from early dialysis initiation as indicated by the eGFR. Even today, the optimal dialysis initiation time remains unknown. The decision of when to start dialysis should be based on careful clinical evaluation.

Minimization vs tailoring: Where do we stand with personalized immunosuppression during renal transplantation in 2015?

The introduction of novel immunosuppressive agents over the last two decades and the improvement of our diagnostic tools for early detection of antibody-mediated injury offer us an opportunity, if not a mandate, to better match the immunosuppression needs of the individual patients with side effects of the therapy. However, immunosuppressive regimens in the majority of programs remain mostly protocol-driven, with relatively little inter-program heterogeneity in certain areas of the world. Emerging data showing different outcomes with a particular immunosuppressive strategy in populations with varying immunological risks underscore a real potential for "personalized medicine" in renal transplantation. Studies demonstrating marked differences in the adverse-effect profiles of individual drugs including the risk for viral infections, malignancy and renal toxicity call for a paradigm shift away from a "one size fits all" approach to an individually tailored immunosuppressive therapy for renal transplant recipients, assisted by both screening for predictors of graft loss and paying close attention to dose or class-related adverse effects. Our paper explores some of the opportunities during the care of these patients. Potential areas of improvements may include: (1) a thorough assessment of immunological and metabolic risk profile of each renal transplant recipient; (2) screening for predictors of graft loss and early signs of antibody-mediated rejection with donor-specific antibodies, protocol biopsies and proteinuria (including close follow up of adverse effects with dose adjustments or conversions as necessary); and (3) increased awareness of the possible link between poor tolerance of a given drug at a given dose and non-adherence with the prescribed regimen. Altogether, these considerations may enable the most effective use of the drugs we already have.

Pentoxifylline decreases serum levels of tumor necrosis factor alpha, interleukin 6 and C-reactive protein in hemodialysis patients: results of a randomized double-blind, controlled clinical trial

AIM

The aim of this study was to compare the effect of pentoxifylline versus placebo on serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) and C-reactive protein (CRP) of hemodialysis (HD) patients.

METHODS

This is a randomized double-blind, controlled clinical trial. HD patients without infection or drugs with anti-inflammatory effect were randomly allocated to a study (n = 18, pentoxifylline 400 mg/day) or control (n = 18, placebo) group; all patients had arteriovenous fistula. Besides clinical and laboratory monthly assessments, serum TNF-α and IL-6 (ELISA) and CRP (nephelometry) were measured at 0, 2 and 4 months.

RESULTS

All the inflammation markers significantly (P < 0.05) decreased in the pentoxifylline group: TNF-α [baseline 0.4 (0-2) versus final 0 (0-0) pg/mL], IL-6 [baseline 9.4 (5-14) versus final 2.9 (2-5) pg/mL] and CRP [baseline 7.1 (3-20) versus final 2.6 (1-8) mg/L], whereas no significant changes were observed in the placebo group: TNF-α [baseline 0 (0-0) versus final 1.2 (0-4) pg/mL], IL-6 [baseline 8.0 (5-11) versus final 8.7 (4-11) pg/mL] and CRP [baseline 4.5 (2-9) versus final 3.8 (3-23) mg/L].

CONCLUSIONS

Pentoxifylline significantly decreased serum concentrations of TNF-α, IL-6 and CRP compared to placebo. Pentoxifylline could be a promising and useful strategy to reduce the systemic inflammation frequently observed in patients on HD.

Fluid overload at initiation of renal replacement therapy is associated with lack of renal recovery in patients with acute kidney injury

BACKGROUND

Patients with acute kidney injury (AKI) requiring initiation of renal replacement therapy (RRT) have poor short- and long-term outcomes, including the development of dialysis dependence. Currently, little is known about what factors may predict renal recovery in this population.

METHODS

We conducted a single-center, retrospective analysis of 170 hospitalized adult patients with AKI attributed to acute tubular necrosis who required inpatient initiation of RRT. Data collection included patient characteristics, laboratory data, details of hospital course and degree of fluid overload at RRT initiation. The primary outcome was recovery of renal function to dialysis independence.

RESULTS

Within 1 year of RRT initiation, 35.9% (61/170) of patients reached the primary end point of renal recovery. The median (interquartile range) duration of RRT was 11 (3-33) days and 83.6% (51/61) recovered prior to hospital discharge. Recovering patients had significantly less fluid overload at the time of RRT initiation compared to non-recovering patients (3.5 versus 9.3%, P = 0.004). In multivariate Cox proportional hazard regression analysis, a rise in percent fluid overload at dialysis initiation remained a significant negative predictor of renal recovery (hazard ratio 0.97, 95% confidence interval 0.95-1.00, P = 0.024).

CONCLUSIONS

In patients with AKI, a higher degree of fluid overload at RRT initiation predicts worse renal recovery at 1 year. Clinical trials are needed to determine whether interventions targeting fluid overload may improve patient and renal outcomes.

Is systemic inflammation of hemodialysis patients improved with the use of enalapril? Results of a randomized, double-blinded, placebo-controlled clinical trial

This study compared the effect of enalapril versus placebo on serum tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and C-reactive protein (CRP) in hemodialysis in a randomized, double- blinded, controlled clinical trial. Patients without infection or antiinflammatory drugs were randomly allocated to a study (n = 13, enalapril, 20 mg/day) or control (n = 12, placebo) group; all had arteriovenous fistula. Serum TNF-alpha, IL-6, and CRP were measured at 0, 1, and 3 months. Systolic blood pressure (baseline vs. final) was 151 +/- 25 vs. 135 +/- 19 mm Hg (p < 0.05) in the study group and 154 +/- 21 vs. 144 +/- 27 mm Hg in control group; diastolic blood pressure was 86 +/- 9 vs. 76 +/- 13 and 91 +/- 16 vs. 81 +/- 18 mm Hg, respectively; median (percentiles 25%-75%) IL-6 (baseline vs. final) was 4.2 (3-8) vs. 4.1 (2-9) pg/mL and 6.3 (3-9) vs. 6.7 (3-8) pg/mL; and CRP was 1.9 (1-7) vs. 3.0 (1-12) mg/L and 4.7 (1-16) vs. 3.9 (2-16) mg/L, respectively. TNF-alpha was detected in only two patients. Enalapril significantly reduced blood pressure in hemodialysis patients, but it did not decrease IL-6 and CRP compared with placebo.