Comparison of biochemical, haematological and volume parameters in two treatment schedules of nocturnal home haemodialysis

Intracellular Phosphate and ATP Depletion Measured by Magnetic Resonance Spectroscopy in Patients Receiving Maintenance Hemodialysis

BACKGROUND

The precise origin of phosphate that is removed during hemodialysis remains unclear; only a minority comes from the extracellular space. One possibility is that the remaining phosphate originates from the intracellular compartment, but there have been no available data from direct assessment of intracellular phosphate in patients undergoing hemodialysis.

METHODS

We used phosphorus magnetic resonance spectroscopy to quantify intracellular inorganic phosphate (Pi), phosphocreatine (PCr), and βATP. In our pilot, single-center, prospective study, 11 patients with ESKD underwent phosphorus (31P) magnetic resonance spectroscopy examination during a 4-hour hemodialysis treatment. Spectra were acquired every 152 seconds during the hemodialysis session. The primary outcome was a change in the PCr-Pi ratio during the session.

RESULTS

During the first hour of hemodialysis, mean phosphatemia decreased significantly (-41%; P<0.001); thereafter, it decreased more slowly until the end of the session. We found a significant increase in the PCr-Pi ratio (+23%; P=0.001) during dialysis, indicating a reduction in intracellular Pi concentration. The PCr-βATP ratio increased significantly (+31%; P=0.001) over a similar time period, indicating a reduction in βATP. The change of the PCr-βATP ratio was significantly correlated to the change of depurated Pi.

CONCLUSIONS

Phosphorus magnetic resonance spectroscopy examination of patients with ESKD during hemodialysis treatment confirmed that depurated Pi originates from the intracellular compartment. This finding raises the possibility that excessive dialytic depuration of phosphate might adversely affect the intracellular availability of high-energy phosphates and ultimately, cellular metabolism. Further studies are needed to investigate the relationship between objective and subjective effects of hemodialysis and decreases of intracellular Pi and βATP content.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Intracellular Phosphate Concentration Evolution During Hemodialysis by MR Spectroscopy (CIPHEMO), NCT03119818.

Nocturnal haemodialysis is associated with a reduced occurrence of low triiodothyronine serum levels in haemodialysed patients

Background

End-stage renal disease (ESRD) is associated with a broad spectrum of morphological and functional thyroid disorders. Recent studies have shown that low free triiodothyronine (fT3) levels are related to inflammatory status and endothelial activation in ESRD patients on haemodialysis (HD). Limited data exist about a possible relationship between dialysis regimen, namely long nocturnal haemodialysis (LNHD), and thyroid function parameters. The aim of this study was to evaluate the relationship between dialysis regimen and thyroid function, and consequently with the main patient outcomes.

Methods

To this purpose, we performed a retrospective, single-centre cohort study including 220 incident chronic HD patients treated during an 8-year period (from January 2010 to December 2017). The main clinical and haematochemical parameters, including thyroid function, were evaluated and related to the main patient outcomes.

Results

Patients with low fT3 levels (<3.05 ng/mL) showed significantly lower survival rates than patients with normal fT3 levels (>3.05 ng/mL) (P < 0.001), although there were no substantial differences in the demographic and clinical characteristics between the two groups. After propensity score 1:3 matching of 25 patients treated with nocturnal HD to 75 patients treated with diurnal HD, LNHD patients showed significantly higher survival rates (88.0% versus 61.3%, P = 0.001) and lower incidence of cardiovascular events than patients on diurnal dialysis (8.0% versus 40.0%, P = 0.001). Moreover, an 8-year time-dependent analysis showed that at any time, except for baseline, the rate of patients with fT3 levels >3.05 ng/mL was significantly higher in LNHD patients than in patients treated with diurnal dialysis.

Conclusions

Our data suggest that the application of alternative dialysis regimens, also reducing the frequency of low T3, could ameliorate outcomes and therefore reduce the incidence of cardiovascular events in HD patients.

High-Intensity Hemodialysis: The Wave of the Future?

Various modalities of high-intensity hemodialysis are gathering increasing popularity. Some of the advantages of these new dialysis regimens are presented. Time and the increasing use of these novel approaches will ultimately determine their role in the overall management of patients with end-stage renal disease.

Nutritional Status in Nocturnal Hemodialysis Patients - A Systematic Review with Meta-Analysis

Background

Hemodialysis patients experience an elevated risk of malnutrition associated with increased morbidity and mortality. Nocturnal hemodialysis (NHD) results in more effective removal of waste products and fluids. Therefore, diet and fluid restrictions are less restricted in NHD patients. However, it is ambiguous whether transition from conventional hemodialysis (CHD) to NHD leads to improved intake and nutritional status. We studied the effect of NHD on protein intake, laboratory indices of nutritional status, and body composition.

Study design

Systematic review with meta-analysis.

Population

NHD patients.

Search strategy

Systematic literature search from databases, Medline, Cinahl, EMBASE and The Cochrane Library, to identify studies reporting on nutritional status post-transition from CHD to NHD.

Intervention

Transition from CHD to NHD.

Outcomes

Albumin, normalized protein catabolic rate (nPCR), dry body weight (DBW), body mass index (BMI), phase angle, protein intake, and energy intake.

Results

Systematic literature search revealed 13 studies comprising 282 patients that made the transition from CHD to NHD. Meta-analysis included nine studies in 229 patients. In control group controlled studies (n = 4), serum albumin increased significantly from baseline to 4–6 months in NHD patients compared with patients that remained on CHD (mean difference 1.3 g/l, 95% CI 0.02; 2.58, p = 0.05). In baseline controlled studies, from baseline to 4–6 months of NHD treatment, significant increases were ascertained in serum albumin (mean difference (MD) 1.63 g/l, 95% CI 0.73–2.53, p<0.001); nPCR (MD 0.16 g/kg/day; 95% CI 0.04–0.29, p = 0.01); protein intake (MD 18.9 g, 95% CI 9.7–28.2, p<0.001); and energy intake (MD 183.2 kcal, 95% CI 16.8–349.7, p = 0.03). Homogeneity was rejected only for nPCR (baseline versus 4–6 months). DBW, BMI, and phase angle did not significantly change. Similar results were obtained for comparison between baseline and 8–12 months of NHD treatment.

Limitations

Most studies had moderate sample sizes; some had incomplete dietary records and relatively brief follow-up period. Studies markedly differed with regard to study design.

Conclusions

NHD is associated with significantly higher protein and energy intake as well as increases in serum albumin and nPCR. However, the data on body composition are inconclusive.

Dialysate calcium concentration and mineral metabolism in long and long-frequent hemodialysis: a systematic review and meta-analysis for a Canadian Society of Nephrology clinical practice guideline

BACKGROUND

Patients treated with conventional hemodialysis (HD) develop disorders of mineral metabolism that are associated with increased morbidity and mortality. More frequent and longer HD has been associated with improvement in hyperphosphatemia that may improve outcomes.

STUDY DESIGN

Systematic review and meta-analysis to inform the clinical practice guideline on intensive dialysis for the Canadian Society of Nephrology.

SETTING & POPULATION

Adult patients receiving outpatient long (≥5.5 hours/session; 3-4 times per week) or long-frequent (≥5.5 hours/session, ≥5 sessions per week) HD.

SELECTION CRITERIA FOR STUDIES

We included clinical trials, cohort studies, case series, case reports, and systematic reviews.

INTERVENTIONS

Dialysate calcium concentration ≥1.5 mmol/L and/or phosphate additive.

OUTCOMES

Fragility fracture, peripheral arterial and coronary artery disease, calcific uremic arteriolopathy, mortality, intradialytic hypotension, parathyroidectomy, extraosseous calcification, markers of mineral metabolism, diet liberalization, phosphate-binder use, and muscle mass.

RESULTS

21 studies were identified: 2 randomized controlled trials, 2 reanalyses of data from the randomized controlled trials, and 17 observational studies. Dialysate calcium concentration ≥1.5 mmol/L for patients treated with long and long-frequent HD prevents an increase in parathyroid hormone levels and a decline in bone mineral density without causing harm. Both long and long-frequent HD were associated with a reduction in serum phosphate level of 0.42-0.45 mmol/L and a reduction in phosphate-binder use. There was no direct evidence to support the use of a dialysate phosphate additive.

LIMITATIONS

Almost all the available information is related to changes in laboratory values and surrogate outcomes.

CONCLUSIONS

Dialysate calcium concentration ≥1.5 mmol/L for most patients treated with long and long-frequent dialysis prevents an increase in parathyroid hormone levels and decline in bone mineral density without increased risk of calcification. It seems prudent to add phosphate to the dialysate for patients with a low predialysis phosphate level or very low postdialysis phosphate level until more evidence becomes available.

Home haemodialysis dose: how much of a good thing?

BACKGROUND

Home dialysis (peritoneal or haemodialysis) in any reasonable guise offers potential benefits compared with in-centre dialysis. Benefits may be overtly patient centred (independence, quality of life), outcome oriented (survival, resolution of left ventricular hypertrophy) or resource friendly (savings on staff costs). The priority placed on each of these areas is likely to vary from patient to patient, and possibly provider to provider. This is the one strength of home haemodialysis (HHD) rather than being viewed as a weakness, as it can offer different benefits to different people. Intuitively, more haemodialysis is better than less, and this is most realistically achieved at home. Indications are that both long nocturnal dialysis and short daily dialysis can offer real objective benefits.

LITERATURE REVIEW

Critics argue correctly that there is a paucity of robust randomised controlled study data. The complexity of HHD regimens and practice and in-homogeneity of patients means such firm data are unlikely to be forthcoming. However, the positive reports both subjective and objective of patients dialysing at home, and results from the available research suggest that advantages may be seen purely with changing the location of dialysis to home, and independently with enhancing dialysis schedules.

CONCLUSION

The logical conclusion is that patients undertaking haemodialysis at home should have at least the recommended minimum of four hours three times per week (or equivalent), preferably avoiding the long inter-dialytic interval, but beyond that rigid adherence to a schedule as dogma should be subjugated to patient choice and flexibility, albeit by prior agreement with supervising medical and nursing staff.

Intensified hemodialysis regimens: neglected treatment options for children and adolescents

During recent years, the importance of intensified dialysis regimens has gathered increasing interest, especially after the Hemodialysis (HEMO) Study Group reported that a higher dose of thrice-weekly hemodialysis failed to improve clinical outcomes. Long nocturnal hemodialysis (three to six times per week) or short daily hemodialysis are the currently used forms of intensified dialysis. There is substantial evidence for cardiovascular and quality-of-life improvements as well as financial benefits with intensified hemodialysis. Preliminary experience with daily hemodialysis and hemodiafiltration in children has been reported. Given the continuing shortage of donor organs for kidney transplantation, the increasing incidence of end-stage renal disease (ESRD) and recognition of the deleterious effects of long-lasting ESRD, growth retardation, and poor social rehabilitation, more intensified dialysis regimens are a much-needed therapeutical option in both adults and children.

Changes in hemoglobin and albumin concentration during nocturnal home hemodialysis

The hemoglobin (Hb) and the serum albumin (S.Alb) concentration commonly rise during seated, conventional thrice-weekly 4 to 4.5 hr hemodialysis (CHD) as a result of rapid fluid removal from the intravascular compartment. Conversely, in long, slow, recumbent nocturnal home hemodialysis (NHHD), the intra-dialytic S.Alb concentration has been shown to fall. In normal human physiology, plasma volume expansion rapidly follows recumbency and is sustained until a resumption of an upright position re-induces plasma volume contraction. The plasma protein dilution of recumbency has been suggested as the mechanism behind this finding in NHHD. Our retrospective analysis of 585 consecutive measurements of predialysis and postdialysis S.Alb and Hb taken from 71 NHHD patients confirmed an intra-dialytic fall in S.Alb (0.99% in alternate night NHHD and 1.4% in 6 nights/week NHHD) compared with an 8.4% rise in a control group of 104 CHD patients (p<0.001). Although the NHHD intra-dialytic Hb rose (3.8% in alternate night NHHD and 2.6% in 6 nights/week NHHD), this rise was significantly greater (8%) in CHD patients (p<0.001), and as physiological data confirm that recumbent dilution for albumin is greater than that for Hb, this may provide the explanation. We conclude that NHHD provides a more physiological volume milieu with the normal physiological dilution mechanisms of recumbency still operating despite the slow, steady volume reduction that accompanied longer hour and more frequent dialysis. These mechanisms are subverted, however, in CHD by the more-aggressive plasma contraction needed to attain adequate control of the intravascular volume in the face of shorter hour, less-frequent dialysis.