Conversion from conventional to nocturnal hemodialysis improves vitamin D levels

Home versus in-centre haemodialysis for people with kidney failure

BACKGROUND

Home haemodialysis (HHD) may be associated with important clinical, social or economic benefits. However, few randomised controlled trials (RCTs) have evaluated HHD versus in-centre HD (ICHD). The relative benefits and harms of these two HD modalities are uncertain. This is an update of a review first published in 2014. This update includes non-randomised studies of interventions (NRSIs).

OBJECTIVES

To evaluate the benefits and harms of HHD versus ICHD in adults with kidney failure.

SEARCH METHODS

We contacted the Information Specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 9 October 2022 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov. We searched MEDLINE (OVID) and EMBASE (OVID) for NRSIs.

SELECTION CRITERIA

RCTs and NRSIs evaluating HHD (including community houses and self-care) compared to ICHD in adults with kidney failure were eligible. The outcomes of interest were cardiovascular death, all-cause death, non-fatal myocardial infarction, non-fatal stroke, all-cause hospitalisation, vascular access interventions, central venous catheter insertion/exchange, vascular access infection, parathyroidectomy, wait-listing for a kidney transplant, receipt of a kidney transplant, quality of life (QoL), symptoms related to dialysis therapy, fatigue, recovery time, cost-effectiveness, blood pressure, and left ventricular mass.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed if the studies were eligible and then extracted data. The risk of bias was assessed, and relevant outcomes were extracted. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Meta-analysis was performed on outcomes where there was sufficient data.

MAIN RESULTS

From the 1305 records identified, a single cross-over RCT and 39 NRSIs proved eligible for inclusion. These studies were of varying design (prospective cohort, retrospective cohort, cross-sectional) and involved a widely variable number of participants (small single-centre studies to international registry analyses). Studies also varied in the treatment prescription and delivery (e.g. treatment duration, frequency, dialysis machine parameters) and participant characteristics (e.g. time on dialysis). Studies often did not describe these parameters in detail. Although the risk of bias, as assessed by the Newcastle-Ottawa Scale, was generally low for most studies, within the constraints of observational study design, studies were at risk of selection bias and residual confounding. Many study outcomes were reported in ways that did not allow direct comparison or meta-analysis. It is uncertain whether HHD, compared to ICHD, may be associated with a decrease in cardiovascular death (RR 0.92, 95% CI 0.80 to 1.07; 2 NRSIs, 30,900 participants; very low certainty evidence) or all-cause death (RR 0.80, 95% CI 0.67 to 0.95; 9 NRSIs, 58,984 patients; very low certainty evidence). It is also uncertain whether HHD may be associated with a decrease in hospitalisation rate (MD -0.50 admissions per patient-year, 95% CI -0.98 to -0.02; 2 NRSIs, 834 participants; very low certainty evidence), compared with ICHD. Compared with ICHD, it is uncertain whether HHD may be associated with receipt of kidney transplantation (RR 1.28, 95% CI 1.01 to 1.63; 6 NRSIs, 10,910 participants; very low certainty evidence) and a shorter recovery time post-dialysis (MD -2.0 hours, 95% CI -2.73 to -1.28; 2 NRSIs, 348 participants; very low certainty evidence). It remains uncertain if HHD may be associated with decreased systolic blood pressure (SBP) (MD -11.71 mm Hg, 95% CI -21.11 to -2.46; 4 NRSIs, 491 participants; very low certainty evidence) and decreased left ventricular mass index (LVMI) (MD -17.74 g/m2, 95% CI -29.60 to -5.89; 2 NRSIs, 130 participants; low certainty evidence). There was insufficient data to evaluate the relative association of HHD and ICHD with fatigue or vascular access outcomes. Patient-reported outcome measures were reported using 18 different measures across 11 studies (QoL: 6 measures; mental health: 3 measures; symptoms: 1 measure; impact and view of health: 6 measures; functional ability: 2 measures). Few studies reported the same measures, which limited the ability to perform meta-analysis or compare outcomes. It is uncertain whether HHD is more cost-effective than ICHD, both in the first (SMD -1.25, 95% CI -2.13 to -0.37; 4 NRSIs, 13,809 participants; very low certainty evidence) and second year of dialysis (SMD -1.47, 95% CI -2.72 to -0.21; 4 NRSIs, 13,809 participants; very low certainty evidence).

AUTHORS' CONCLUSIONS

Based on low to very low certainty evidence, HHD, compared with ICHD, has uncertain associations or may be associated with decreased cardiovascular and all-cause death, hospitalisation rate, slower post-dialysis recovery time, and decreased SBP and LVMI. HHD has uncertain cost-effectiveness compared with ICHD in the first and second years of treatment. The majority of studies included in this review were observational and subject to potential selection bias and confounding, especially as patients treated with HHD tended to be younger with fewer comorbidities. Variation from study to study in the choice of outcomes and the way in which they were reported limited the ability to perform meta-analyses. Future research should align outcome measures and metrics with other research in the field in order to allow comparison between studies, establish outcome effects with greater certainty, and avoid research waste.

Nocturnal hemodialysis: improved quality of life and patient outcomes

Conventional hemodialysis is associated with high morbidity and mortality rates, as well as a reduced quality of life. There is a growing interest in the provision of more intensive hemodialysis, due to associated benefits in terms of reduced cardiovascular morbidity, better regulation of mineral metabolism, as well as its impact on quality of life measures, fertility, and sleep. Nocturnal hemodialysis, both in center and at home, allows the delivery of more intensive hemodialysis. This review discusses the benefits of nocturnal hemodialysis and evaluates the evidence based on available literature.

The choice of dialysate sodium is influenced by hemodialysis frequency and duration: what should it be and for what modality?

Cardiovascular disease is the leading cause of mortality in hemodialysis patients. A chronic state of volume and pressure overload contributes, and central to this is the net sodium balance over the course of a hemodialysis. Of recent interest is the contribution of the dialysate sodium concentration (Dial-Na+) to clinical outcomes. Abundant evidence confirms that in thrice-weekly conventional hemodialysis, higher Dial-Na+ associates with increased intradialytic weight gain, blood pressure, and cardiovascular morbidity and mortality. On the other hand, low Dial-Na+ associates with intradialytic hypotension in the same patient population. However, the effect of Dial-Na+ in short hours daily hemodialysis (SHD; often referred to as "quotidian" dialysis), or nocturnal dialysis (FHND) is less well studied. Increased frequency and duration of exposure to a diffusive sodium gradient modulate the way in which DPNa+ alters interdialytic weight gain, predialysis blood pressure, and intradialytic change in blood pressure. Furthermore, increased dialysis frequency appears to decrease the predialysis plasma sodium setpoint (SP), which is considered stable in conventional thrice-weekly patients. This review discusses criteria to determine optimal Dial-Na+ in conventional, SHD and FHND patients, and identifies areas for future research.

Fibroblast growth factor 23 and left ventricular mass index in maintenance hemodialysis patients: standard versus long nocturnal hemodialysis

Elevated levels of fibroblast growth factor 23 (FGF23) and phosphorus (P) have been linked to greater risks of left ventricular hypertrophy (LVH) in patients with end stage renal disease (ESRD). The aim of this study was to test if differences exist in a long nocturnal HD group in comparison with a group treated with standard daily thrice weekly dialysis. The attempt was to evaluate if elevated FGF-23 levels, intact parathyroid hormone and P might be associated with left ventricular mass index (LVMI). Quantitative echocardiographic analyses were performed at baseline in 50 maintenance HD patients (17 women and 33 men, mean age: 56.4 ± 15.35 years, mean HD vintage: 9.06 ± 8.86 years, all patients are on HD thrice a week-median duration 15 h/week, 10 of them on long nocturnal HD, median duration 24 h/week). LVMIs were calculated. FGF23 was measured in duplicate using a second generation C-terminal enzyme-linked immunosorbent assay and log of FGF-23 values were computed. Mean LVMI was 136.44 ± 44.44 g/m(2) . Serum FGF-23 levels were elevated when compared to population data with preserved kidney function (median 1388.5 RU/mL, range 252 to 24 336 RU/mL). There were no correlations recorded between log FGF-23 levels and LVMI (r = 0.2, P = 0.66). LVMI was significantly lower in HD patients on long nocturnal dialysis procedure (r = -0.31, P = 0.05). Patients treated with long nocturnal HD showed lower LV mass, lower P-values and higher 25-OH-D3 supply. Plasma FGF-23 concentration was comparable between the groups and was not associated with LVMI in our maintenance HD patients.

Calcidiol deficiency in end-stage organ failure and after solid organ transplantation: status quo

Among patients with organ failure, vitamin D deficiency is extremely common and frequently does not resolve after transplantation. This review crystallizes and summarizes existing data on the status quo of vitamin D deficiency in patients with organ failure and in solid organ transplant recipients. Interventional studies evaluating different treatment strategies, as well as current clinical practice guidelines and recommendations on the management of low vitamin D status in these patients are also discussed.

Vitamin d and stage 5 chronic kidney disease: a new paradigm?

Vitamin D receptor agonists (VDRA) are currently recommended for the treatment of secondary hyperparathyroidism in stage 5 CKD. They are considered to be contraindicated in the presence of low or normal (for a dialysis patient) levels of PTH due to the risk of developing adynamic bone disease, with consequent vascular calcification. However, these recommendations are increasingly at odds with the epidemiological evidence, which consistently shows a large survival advantage for patients treated with low-dose VDRAs, regardless of plasma calcium, phosphate, or PTH. A large number of pleiotropic effects of vitamin D have been described, including inhibition of renin activity, anti-inflammation, and suppression of vascular calcification stimulators and stimulation of vascular calcification inhibitors present in the uremic milieu. Laboratory studies suggest that a normal cellular vitamin D level is necessary for normal cardiomyocyte and vascular smooth muscle function. While pharmacological doses of VDRA can be harmful, the present evidence suggests that the level of 1,25-dihydroxycholecalciferol should also be more physiological in stage 5 CKD, and that widespread use of low-dose VDRA would be beneficial. A randomized controlled trial to test this hypothesis is warranted.

A hospital-based intermittent nocturnal hemodialysis program for children and adolescents

OBJECTIVE

To establish a hospital-based nocturnal hemodialysis (NHD) program for children and adolescents.

STUDY DESIGN

Sixteen patients (age, 0.5 to 17 years) were prospectively included. Uremia-associated measures as well as amount and dosage of medication were enumerated. Quality of life also was evaluated. Results were compared with data of the same patients on conventional hemodialysis and with matched control subjects (conventional HD).

RESULTS

NHD was well tolerated. Median Kt/V values increased. Predialytic mean arterial pressure, urea, phosphate, and parathyroid hormone levels decreased. There was an increase in protein catabolic rate. Dietary and fluid restrictions could be lifted. Amount and dosage of phosphate and potassium binders and antihypertensive medication could be reduced. Quality of life improved and days of absence from school decreased in all patients.

CONCLUSIONS

In addition to a better control of uremia-associated measures, NHD allows free dietary and fluid intake and improves patient well-being. Given the continuing shortage of donor organs for kidney transplantation and the high morbidity and mortality on conventional HD, intensified dialysis regimens are a much-needed therapeutic option.

Vitamin D in solid organ transplantation with special emphasis on kidney transplantation

Within the past decades, vitamin D was identified as having additional physiological functions far beyond calcium homeostasis and bone metabolism. Stimulated by the discovery of the vitamin D receptor in a broad range of tissues as well as the expression of 1α-hydroxylase, the enzyme responsible for the activation of vitamin D, it became evident that the actions of vitamin D are not restricted to cells involved in mineral and bone metabolism. In fact, it affects proliferation, differentiation, and function of a large number of different cell types including cells of the immune system. Vitamin D receptor agonists were found to exert immunosuppressive effects on the adaptive immune system, thus being able to mediate immunologic tolerance. However, they promote the innate immune system and thereby improve the ability of the host to combat invading pathogens. This review summarizes our current understanding of vitamin D as an immunomodulatory agent with special emphasis on its clinical implications in the transplant setting.

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.

Phosphorus control in peritoneal dialysis patients

Hyperphosphatemia is independently associated with an increased risk of death among dialysis patients. In this study, we have assessed the status of phosphate control and its clinical and laboratory associations in a large international group of patients on chronic peritoneal dialysis (PD) treatment. This cross-sectional multicenter study was carried out in 24 centers in three different countries (Canada, Greece, and Turkey) among 530 PD patients (235 women, 295 men) with a mean+/-s.d. age of 55+/-16 years and mean duration of PD of 33+/-25 months. Serum calcium (Ca(2+)), ionized Ca(2+), phosphate, intact parathyroid hormone (iPTH), 25-hydroxy vitamin D(3), 1,25-dihydroxy vitamin D(3), total alkaline phosphatase, and bone alkaline phosphatase concentrations were investigated, along with adequacy parameters such as Kt/V, weekly creatinine clearance, and daily urine output. Mean Kt/V was 2.3+/-0.65, weekly creatinine clearance 78.5+/-76.6 l, and daily urine output 550+/-603 ml day(-1). Fifty-five percent of patients had a urine volume of <400 ml day(-1). Mean serum phosphorus level was 4.9+/-1.3 mg per 100 ml, serum Ca(2+) 9.4+/-1.07 mg per 100 ml, iPTH 267+/-356 pg ml(-1), ionized Ca(2+) 1.08+/-0.32 mg per 100 ml, calcium phosphorus (Ca x P) product 39+/-19 mg(2)dl(-2), 25(OH)D(3) 8.3+/-9.3 ng ml(-1), 1,25(OH)(2)D(3) 9.7+/-6.7 pg ml(-1), total alkaline phosphatase 170+/-178 U l(-1), and bone alkaline phosphatase 71+/-108 U l(-1). While 14% of patients were hypophosphatemic, with a serum phosphorus level lower than 3.5 mg per 100 ml, most patients (307 patients, 58%) had a serum phosphate level between 3.5 and 5.5 mg per 100 ml. Serum phosphorus level was 5.5 mg per 100 ml or greater in 28% (149) of patients. Serum Ca(2+) level was > or =9.5 mg per 100 ml in 250 patients (49%), between 8.5 and 9.5 mg per 100 ml in 214 patients (40%), and lower than 8.5 mg per 100 ml in 66 patients (12%). Ca x P product was >55 mg(2)dl(-2) in 136 patients (26%) and lower than 55 mg(2)dl(-2) in 394 patients (74%). Serum phosphorus levels were positively correlated with serum albumin (P<0.027) and iPTH (P=0.001), and negatively correlated with age (P<0.033). Serum phosphorus was also statistically different (P = 0.013) in the older age group (>65 years) compared to younger patients; mean levels were 5.1+/-1.4 and 4.5+/-1.1 mg per 100 ml, respectively, in the two groups. In our study, among 530 PD patients, accepted uremic-normal limits of serum phosphorus control was achieved in 58%, Ca x P in 73%, serum Ca(2+) in 53%, and iPTH levels in 24% of subjects. Our results show that chronic PD, when combined with dietary measures and use of phosphate binders, is associated with satisfactory serum phosphorus control in the majority of patients.