Peritoneal dialysis versus haemodialysis for people commencing dialysis

BACKGROUND

Peritoneal dialysis (PD) and haemodialysis (HD) are two possible modalities for people with kidney failure commencing dialysis. Only a few randomised controlled trials (RCTs) have evaluated PD versus HD. The benefits and harms of the two modalities remain uncertain. This review includes both RCTs and non-randomised studies of interventions (NRSIs).

OBJECTIVES

To evaluate the benefits and harms of PD, compared to HD, in people with kidney failure initiating dialysis.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies from 2000 to June 2024 using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov. MEDLINE and EMBASE were searched for NRSIs from 2000 until 28 March 2023.

SELECTION CRITERIA

RCTs and NRSIs evaluating PD compared to HD in people initiating dialysis were eligible.

DATA COLLECTION AND ANALYSIS

Two investigators independently assessed if the studies were eligible and then extracted data. Risk of bias was assessed using standard Cochrane methods, and relevant outcomes were extracted for each report. The primary outcome was residual kidney function (RKF). Secondary outcomes included all-cause, cardiovascular and infection-related death, infection, cardiovascular disease, hospitalisation, technique survival, life participation and fatigue.

MAIN RESULTS

A total of 153 reports of 84 studies (2 RCTs, 82 NRSIs) were included. Studies varied widely in design (small single-centre studies to international registry analyses) and in the included populations (broad inclusion criteria versus restricted to more specific participants). Additionally, treatment delivery (e.g. automated versus continuous ambulatory PD, HD with catheter versus arteriovenous fistula or graft, in-centre versus home HD) and duration of follow-up varied widely. The two included RCTs were deemed to be at high risk of bias in terms of blinding participants and personnel and blinding outcome assessment for outcomes pertaining to quality of life. However, most other criteria were assessed as low risk of bias for both studies. Although the risk of bias (Newcastle-Ottawa Scale) was generally low for most NRSIs, studies were at risk of selection bias and residual confounding due to the constraints of the observational study design. In children, there may be little or no difference between HD and PD on all-cause death (6 studies, 5752 participants: RR 0.81, 95% CI 0.62 to 1.07; I2 = 28%; low certainty) and cardiovascular death (3 studies, 7073 participants: RR 1.23, 95% CI 0.58 to 2.59; I2 = 29%; low certainty), and was unclear for infection-related death (4 studies, 7451 participants: RR 0.98, 95% CI 0.39 to 2.46; I2 = 56%; very low certainty). In adults, compared with HD, PD had an uncertain effect on RKF (mL/min/1.73 m2) at six months (2 studies, 146 participants: MD 0.90, 95% CI 0.23 to 3.60; I2 = 82%; very low certainty), 12 months (3 studies, 606 participants: MD 1.21, 95% CI -0.01 to 2.43; I2 = 81%; very low certainty) and 24 months (3 studies, 334 participants: MD 0.71, 95% CI -0.02 to 1.48; I2 = 72%; very low certainty). PD had uncertain effects on residual urine volume at 12 months (3 studies, 253 participants: MD 344.10 mL/day, 95% CI 168.70 to 519.49; I2 = 69%; very low certainty). PD may reduce the risk of RKF loss (3 studies, 2834 participants: RR 0.55, 95% CI 0.44 to 0.68; I2 = 17%; low certainty). Compared with HD, PD had uncertain effects on all-cause death (42 studies, 700,093 participants: RR 0.87, 95% CI 0.77 to 0.98; I2 = 99%; very low certainty). In an analysis restricted to RCTs, PD may reduce the risk of all-cause death (2 studies, 1120 participants: RR 0.53, 95% CI 0.32 to 0.86; I2 = 0%; moderate certainty). PD had uncertain effects on both cardiovascular (21 studies, 68,492 participants: RR 0.96, 95% CI 0.78 to 1.19; I2 = 92%) and infection-related death (17 studies, 116,333 participants: RR 0.90, 95% CI 0.57 to 1.42; I2 = 98%) (both very low certainty). Compared with HD, PD had uncertain effects on the number of patients experiencing bacteraemia/bloodstream infection (2 studies, 2582 participants: RR 0.34, 95% CI 0.10 to 1.18; I2 = 68%) and the number of patients experiencing infection episodes (3 studies, 277 participants: RR 1.23, 95% CI 0.93 to 1.62; I2 = 20%) (both very low certainty). PD may reduce the number of bacteraemia/bloodstream infection episodes (2 studies, 2637 participants: RR 0.44, 95% CI 0.27 to 0.71; I2 = 24%; low certainty). Compared with HD; It is uncertain whether PD reduces the risk of acute myocardial infarction (4 studies, 110,850 participants: RR 0.90, 95% CI 0.74 to 1.10; I2 = 55%), coronary artery disease (3 studies, 5826 participants: RR 0.95, 95% CI 0.46 to 1.97; I2 = 62%); ischaemic heart disease (2 studies, 58,374 participants: RR 0.86, 95% CI 0.57 to 1.28; I2 = 95%), congestive heart failure (3 studies, 49,511 participants: RR 1.10, 95% CI 0.54 to 2.21; I2 = 89%) and stroke (4 studies, 102,542 participants: RR 0.94, 95% CI 0.90 to 0.99; I2 = 0%) because of low to very low certainty evidence. Compared with HD, PD had uncertain effects on the number of patients experiencing hospitalisation (4 studies, 3282 participants: RR 0.90, 95% CI 0.62 to 1.30; I2 = 97%) and all-cause hospitalisation events (4 studies, 42,582 participants: RR 1.02, 95% CI 0.81 to 1.29; I2 = 91%) (very low certainty). None of the included studies reported specifically on life participation or fatigue. However, two studies evaluated employment. Compared with HD, PD had uncertain effects on employment at one year (2 studies, 593 participants: RR 0.83, 95% CI 0.20 to 3.43; I2 = 97%; very low certainty).

AUTHORS' CONCLUSIONS

The comparative effectiveness of PD and HD on the preservation of RKF, all-cause and cause-specific death risk, the incidence of bacteraemia, other vascular complications (e.g. stroke, cardiovascular events) and patient-reported outcomes (e.g. life participation and fatigue) are uncertain, based on data obtained mostly from NRSIs, as only two RCTs were included.

Rate of decline in residual kidney function pre and post peritoneal dialysis initiation: A post hoc analysis of the IDEAL study

Background

Residual kidney function (RKF) is associated with improved survival and quality of life in dialysis patients. Previous studies have suggested that initiation of peritoneal dialysis (PD) may slow RKF decline compared to the pre-dialysis period. We sought to evaluate the association between PD initiation and RKF decline in the Initiating Dialysis Early And Late (IDEAL) trial.

Methods

In this post hoc analysis of the IDEAL randomized controlled trial, PD participants were included if results from 24-hour urine collections had been recorded within 30 days of dialysis initiation, and at least one value pre- and one value post-dialysis commencement were available. The primary outcome was slope of RKF decline, calculated as mean of urinary creatinine and urea clearances. Secondary outcomes included slope of urine volume decline and time from PD initiation to anuria.

Results

The study included 151 participants (79 early start, 72 late start). The slope of RKF decline was slower after PD initiation (-2.69±0.18mL/min/1.73m²/yr) compared to before PD (-4.09±0.33mL/min/1.73m²/yr; change in slope +1.19 mL/min/1.73m²/yr, 95%CI 0.48–1.90, p<0.001). In contrast, urine volume decline was faster after PD commencement (-0.74±0.05 L/yr) compared to beforehand (-0.57±0.06L/yr; change in slope -0.18L/yr, 95%CI -0.34—-0.01, p = 0.04). No differences were observed between the early- and late-start groups with respect to RKF decline, urine volume decline or time to anuria.

Conclusions

Initiation of PD was associated with a slower decline of RKF compared to the pre-dialysis period.

Comparison of Longitudinal Membrane Function in Peritoneal Dialysis Patients According to Dialysis Fluid Biocompatibility

Introduction

Preservation of peritoneal function is essential in long-term peritoneal dialysis. Biocompatible dialysis solutions might prevent or postpone the membrane alteration resulting in ultrafiltration failure and consecutive morbidity and mortality.

Methods

We conducted an observational cohort study in which we made a longitudinal comparison between the course of peritoneal solute and fluid transport during treatment with conventional and biocompatible solutions. Therefore, prospectively collected peritoneal transport data from the yearly standard peritoneal permeability analysis were analyzed in 251 incident patients treated between 1994 and censoring in 2016. Fluid transport included small pore and free water transport. Solute transport was assessed by creatinine mass transfer area coefficient and glucose absorption. Linear mixed models including change point analyses were performed. Interaction with peritonitis was examined.

Results

One hundred thirty-five patients received conventional and 116 biocompatible solutions. Sixty-seven percent (conventional) and 64% (biocompatible) of these underwent minimally three transport measurements. Initially, biocompatible fluids showed higher small solute transport and lower ultrafiltration than conventional fluids up to 3 years. Thereafter, conventional fluids showed an increase in small solute transport (+2.7 ml/min per year; 95% confidence interval [CI]: 0.9 to 4.5) and a decrease of free water transport (−28.0 ml/min per year; 95% CI: −60.4 to 4.4). These were minor or absent in biocompatible treatment. Peritonitis induced a decrease of transcapillary ultrafiltration after 2 years on dialysis with conventional solutions (−291 ml/min per year; 95% CI: −550 to −32) while this was absent in biocompatible treatment.

Conclusion

Despite a higher initial solute transport with biocompatible solutions, these have less influence on functional long-term peritoneal alterations than conventional solutions.

Estimated glomerular filtration rate at dialysis initiation and subsequent decline in residual kidney function among incident hemodialysis patients

BACKGROUND

Higher estimated glomerular filtration rate (eGFR) at dialysis initiation, known as earlier start of dialysis, is often a surrogate of poor outcomes including higher mortality. We hypothesized that earlier dialysis initiation is associated with a faster decline in residual kidney function (RKF), which is also associated with higher mortality among incident hemodialysis (HD) patients.

METHODS

In a cohort of 4911 incident HD patients who initiated HD over a 5-year period (July 2001 to June 2006), we examined the trajectories of RKF, ascertained by renal urea clearance (KRU), over 2 years after HD initiation across strata of eGFR at HD initiation using case-mix adjusted linear mixed-effect models. We then investigated the association between annual change in RKF and mortality using Cox proportional hazard models.

RESULTS

The median (interquartile range) baseline KRU was 2.20 (1.13-3.63)  mL/min/1.73 m2. The decline of KRU was faster in patients who initiated HD at higher eGFR. The relative changes with 95% confidence intervals (CIs) in KRU at 1 year after HD initiation were -1.29 (-1.28 to -1.30), -1.17 (-1.16 to -1.18), -1.11 (-1.10 to -1.12) and -0.78 (-0.78 to -0.79)  mL/min/1.73 m2 in the eGFR categories of ≥10, 8-<10, 6-<8 and <6 mL/min/1.73 m2, respectively. The faster decline of KRU at 1 year was associated with higher all-cause mortality (reference: ≥0 mL/min/1.73 m2): hazard ratios (95% CIs) for change in KRU of -1.5 to <0, -3 to less than -1.5 and less than -3 mL/min/1.73 m2 were 1.20 (1.03-1.40), 1.42 (1.17-1.72) and 1.88 (1.47-2.40), respectively.

CONCLUSIONS

The faster decline of RKF happens with earlier dialysis initiation and is associated with higher all-cause mortality.

Association of Mineral Bone Disorder With Decline in Residual Kidney Function in Incident Hemodialysis Patients

Abnormalities of mineral bone disorder (MBD) parameters have been suggested to be associated with poor renal outcome in predialysis patients. However, the impact of those parameters on decline in residual kidney function (RKF) is uncertain among incident hemodialysis (HD) patients. We performed a retrospective cohort study in 13,772 patients who initiated conventional HD during 2007 to 2011 and survived 6 months of dialysis. We examined the association of baseline serum phosphorus, calcium, intact parathyroid hormone (PTH), and alkaline phosphatase (ALP) with a decline in RKF. Decline in RKF was assessed by estimated slope of renal urea clearance (KRU) over 6 months from HD initiation. Our cohort had a mean ± SD age of 62 ± 15 years; 64% were men, 57% were white, 65% had diabetes, and 51% had hypertension. The median (interquartile range [IQR]) baseline KRU level was 3.4 (2.0, 5.2) mL/min/1.73 m² . The median (IQR) estimated 6-month KRU slope was -1.47 (-2.24, -0.63) mL/min/1.73 m² per 6 months. In linear regression models, higher phosphorus categories were associated with a steeper 6-month KRU slope compared with the reference category (phosphorus 4.0 to <4.5 mg/dL). Lower calcium and higher intact PTH and ALP categories were also associated with a steeper 6-month KRU slope compared with their respective reference groups (calcium 9.2 to <9.5 mg/dL; intact PTH 150 to <250 pg/mL; ALP <60 U/L). The increased number of parameter abnormalities had an additive effect on decline in RKF. Abnormalities of MBD parameters including higher phosphorus, intact PTH, ALP and lower calcium levels were independently associated with decline in RKF in incident HD patients. © 2019 American Society for Bone and Mineral Research. © 2019 American Society for Bone and Mineral Research.

Higher serum phosphorus predicts residual renal function loss in male but not female incident peritoneal dialysis patients

BACKGROUND

Elevated serum phosphorus level is a risk factor for progression of chronic kidney disease in non-dialysis patients. However, the association of serum phosphorus level with residual renal function (RRF) loss among incident continuous ambulatory peritoneal dialysis (CAPD) patients remains unclear.

METHODS

We performed a retrospective analysis of prospectively collected cohort of 1245 incident CAPD patients from January 2006 to December 2015 and followed up until December 2017. Patients were stratified into tertiles according to baseline serum phosphorus levels. RRF loss was defined as residual glomerular filtration rate (mL/min/1.73 m²) reaching zero or estimated urine output less than 200 mL/day on two successive clinic visits. Propensity-score matched Cox's proportional hazards and competing risk models were performed to examine the association of serum phosphorus with RRF loss.

RESULTS

A total of 421 (33.82%) patients had loss of RRF over a median follow-up of 26.23 months. In the entire cohort, elevated serum phosphorus was associated with increased risk for RRF loss after adjustment. In the propensity-score matched cohort, patients in the 3rd tertile of serum phosphorus had a 51% higher risk of RRF loss than those in the combination of the 1st and 2nd tertiles. Furthermore, the association of serum phosphorus level with RRF loss differed by sex (interaction P = 0.018). The adjusted HRs per 1 mg/dL increase in serum phosphorus level of RRF loss were 1.32 (95% CI 1.15-1.50, P < 0.001) for male and 1.03 (95% CI 0.87-1.21, P = 0.750) for female, respectively. These findings persisted in competing risk analysis.

CONCLUSION

Higher serum phosphorus levels independently predicts RRF loss in men treated with CAPD.

Individualized Hemodialysis Treatment: A Perspective on Residual Kidney Function and Precision Medicine in Nephrology

Background: Residual kidney function (RKF) is often expected to inevitably and rapidly decline among hemodialysis patients and, hence, has been inadvertently ignored in clinical practice. The importance of RKF has been revisited in some recent studies. Given that patients with end-stage renal disease now tend to initiate maintenance hemodialysis therapy with higher RKF levels, there seem to be important opportunities for incremental hemo­dialysis by individualizing the dose and frequency according to their RKF levels. This approach is realigned with precision medicine and patient-centeredness. Summary: In this article, we first review the available methods to estimate RKF among hemodialysis patients. We then discuss the importance of maintaining and monitoring RKF levels based on a variety of clinical aspects, including volume overload, blood pressure control, mineral and bone metabolism, nutrition, and patient survival. We also review several potential measures to protect RKF: the use of high-flux and biocompatible membranes, the use of ultrapure dialysate, the incorporation of hemodiafiltration, incremental hemodialysis, and a low-protein diet, as well as general care such as avoiding nephrotoxic events, maintaining appropriate blood pressure, and better control of mineral and bone disorder parameters. Key Message: Individualized hemodialysis regimens may maintain RKF, lead to a better quality of life without compromising long-term survival, and ensure precision medicine and patient-centeredness in nephrology practice.

Lower body mass index and mortality in older adults starting dialysis

Lower body mass index (BMI) has consistently been associated with mortality in elderly in the general and chronic disease populations. Remarkably, in older incident dialysis patients no association of BMI with mortality was found. We performed an in-depth analysis and explored possible time-stratified effects of BMI. 908 incident dialysis patients aged ≥65 years of the NECOSAD study were included, and divided into tertiles by baseline BMI (<23.1 (lower), 23.1–26.0 (reference), ≥26.0 (higher) kg/m²). Because the hazards changed significantly during follow-up, the effect of BMI was modeled for the short-term (<1 year) and longer-term (≥1 year after dialysis initiation). During follow-up (median 3.8 years) 567 deaths occurred. Lower BMI was associated with higher short-term mortality risk (adjusted-HR 1.63 [1.14–2.32] P = 0.007), and lower longer-term mortality risk (adjusted-HR 0.81 [0.63–1.04] P = 0.1). Patients with lower BMI who died during the first year had significantly more comorbidity, and worse self-reported physical functioning compared with those who survived the first year. Thus, lower BMI is associated with increased 1-year mortality, but conditional on surviving the first year, lower BMI yielded a similar or lower mortality risk compared with the reference. Those patients with lower BMI, who had limited comorbidity and better physical functioning, had better survival.

Effect of glomerular filtration rate at dialysis initiation on survival in patients with advanced chronic kidney disease: what is the effect of lead-time bias?

PURPOSE

Current clinical guidelines recommend to initiate dialysis in the presence of symptoms or signs attributable to kidney failure, often with a glomerular filtration rate (GFR) of 5-10 mL/min/1.73 m2. Little evidence exists about the optimal kidney function to start dialysis. Thus far, most observational studies have been limited by lead-time bias. Only a few studies have accounted for lead-time bias, and showed contradictory results. We examined the effect of GFR at dialysis initiation on survival in chronic kidney disease patients, and the role of lead-time bias therein. We used both kidney function based on 24-hour urine collection (measured GFR [mGFR]) and estimated GFR (eGFR).

MATERIALS AND METHODS

A total of 1,143 patients with eGFR data at dialysis initiation and 852 patients with mGFR data were included from the NECOSAD cohort. Cox regression was used to adjust for potential confounders. To examine the effect of lead-time bias, survival was counted from the time of dialysis initiation or from a common starting point (GFR 20 mL/min/1.73 m2), using linear interpolation models.

RESULTS

Without lead-time correction, no difference between early and late starters was present based on eGFR (hazard ratio [HR] 1.03, 95% confidence interval [CI] 0.81-1.3). However, after lead-time correction, early initiation showed a survival disadvantage (HR between 1.1 [95% CI 0.82-1.48] and 1.33 [95% CI 1.05-1.68]). Based on mGFR, the potential survival benefit for early starters without lead-time correction (HR 0.8, 95% CI 0.62-1.03) completely disappeared after lead-time correction (HR between 0.94 [95% CI 0.65-1.34] and 1.21 [95% CI 0.95-1.56]). Dialysis start time differed about a year between early and late initiation.

CONCLUSION

Lead-time bias is not only a methodological problem but also has clinical impact when assessing the optimal kidney function to start dialysis. Therefore, lead-time bias is extremely important to correct for. Taking account of lead-time bias, this controlled study showed that early dialysis initiation (eGFR >7.9, mGFR >6.6 mL/min/1.73 m2) was not associated with an improvement in survival. Based on kidney function, this study suggests that in some patients, dialysis could be started even later than an eGFR <5.7 and mGFR <4.3 mL/min/1.73 m2.

Low Urinary Creatinine Excretion Is Associated With Self-Reported Frailty in Patients With Advanced Chronic Kidney Disease

Introduction

Frailty and muscle wasting, a component of frailty, are common in advanced stage chronic kidney disease (CKD). Whether frailty is associated with low urinary creatinine excretion (UCrE) as a measure of muscle mass in this population is unknown. Furthermore, reference values of UCrE are lacking. We first defined low UCrE and studied correlates of low UCrE, and subsequently studied cross-sectional associations of frailty with low UCrE in patients with advanced CKD.

Methods

A total of 2748 healthy individuals of the general population-based PREVEND study were included to define low UCrE (UCrE indexed for height, below the age- and sex-specific 5th percentile of the distribution). Frailty was defined using a modification of the Fried frailty phenotype. In a CKD population that included 320 and 967 participants of the PREPARE-2 and NECOSAD studies, respectively, cross-sectional associations of self-reported frailty, the individual components that define self-reported frailty, and frailty-associated variables with low UCrE were evaluated using multivariate logistic and linear regression models.

Results

Low UCrE was found in 38% of the CKD patients. A lower glomerular filtration rate was strongly associated with low UCrE. Self-reported frailty (adjusted odds ratio: 2.19; 95% confidence interval: 1.28−3.77) and the individual components were associated with low UCrE, independent of comorbidities. The frailty-associated variables hemoglobin and albumin were inversely associated with low UCrE, and parathyroid hormone was positively associated with low UCrE.

Discussion

Lower kidney function is a strong correlate of low UCrE and self-reported frailty, and the individual frailty components are associated with low UCrE as well, independent of comorbidities.

Diuretics, Limited Ultrafiltration, and Residual Renal Function in Incident Hemodialysis Patients: A Case Series

The effect of diuretics on residual renal function expressed as residual GFR (rGFR) and urine volume (rUV) using 24-hour urine collections has not been well examined in hemodialysis (HD) patients. We present a small (seven patient) but provocative case series describing a strikingly low rate of decline in rUV and rGFR (average of creatinine and urea clearances, 24-hour urine collections) in patients treated with increasing doses of furosemide (up to 360 mg/day) during the first 2 years after initiation of HD. Between 6 and 12 months, the mean rUV fell by 1 ml/month, whereas rGFR declined by 0.03 ml/min/1.73 m(2) /month. The mean rate of decline from 12 to 24 months for rUV (33 ml/month) and rGFR (0.02 ml/min/1.73 m(2) /month) were also low. While data are clearly limited and the observation retrospective, they are consistent with the better documented benefit of diuretics observed in end-stage renal disease patients treated with peritoneal dialysis.

Rate of Decline of Residual Kidney Function Before and After the Start of Peritoneal Dialysis

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BACKGROUND

There is a paucity of information on whether peritoneal dialysis (PD) slows the decline of residual kidney function (RKF) compared to the natural slope of RKF decline prior to dialysis start. Our aim was to analyze the RKF decline before and after initiating PD, and to determine the principal factors affecting this decline during the PD period. ♦

METHODS

We determined individual glomerular filtration rates (GFR) for approximately 12 months before and after PD in 77 new PD patients in a large academic medical center (2008 - 2012). The GFR was estimated by the Modification of Diet in Renal Disease (MDRD) equation in the predialysis period and by averaging 24-hour urine creatinine and urea clearances in the PD period. The rate of RKF decline was calculated using unadjusted linear regression analysis. Wilcoxon signed rank test was used to compare RKF decline before and after PD initiation. Multivariate linear regression was used to identify independent risk factors for RKF decline in the PD phase. ♦

RESULTS

A significantly slower mean rate of RKF decline was observed in the PD period compared with the predialysis period (-0.21 ± 0.30 vs -0.59 ± 0.55 mL/min/1.73 m(2)/month, p < 0.01). Higher baseline RKF, higher serum phosphate, and older age were independently associated with faster decline of RKF (all p < 0.01). ♦

CONCLUSIONS

In patients with advanced chronic kidney disease, initiating PD was associated with a slower rate of RKF decline compared to the rate in the predialysis period.

Dietary Management of Incremental Transition to Dialysis Therapy: Once-Weekly Hemodialysis Combined With Low-Protein Diet

Initiation of thrice-weekly hemodialysis often results in a rapid loss of residual kidney function (RKF) including reduction in urine output. Preserving RKF longer is associated with better outcomes including greater survival in dialysis patients. An alternative approach aimed at preserving RKF is an incremental transition with less frequent hemodialysis sessions at the beginning with gradual increase in hemodialysis frequency over months. In addition to favorable clinical and economic implications, an incremental transition would also enhance a less stressful adaptation of the patient to dialysis therapy. The current guidelines provide only limited recommendations for incremental hemodialysis approach, whereas the potential role of nutritional management of newly transitioned hemodialysis patients is largely overlooked. We have reviewed previous reports and case studies of once-weekly hemodialysis treatment combined with low-protein, low-phosphorus, and normal-to-high-energy diet especially for nondialysis days, whereas on dialysis days, high protein can be provided. Such an adaptive dietary regimen may elicit more favorable outcomes including better preserved RKF, lower β2-microglobulin levels, improved phosphorus control, and lower doses of erythropoiesis-stimulating agents. Clinical and nutritional status and RKF should be closely monitored throughout the transition to once and then twice-weekly regimen and eventually thrice-weekly hemodialysis. Further studies are needed to verify the long-term safety and implications of this approach to dialysis transition.

The first year on haemodialysis: a critical transition

The first year following the start of haemodialysis (HD) is associated with increased mortality, especially during the first 90–120 days after the start of dialysis. Whereas the start of dialysis has important effects on the internal environment of the patient, there are relatively few studies assessing changes in phenotype and underlying mechanisms during the transition period following pre-dialysis to dialysis care, although more insight into these parameters is of importance in unravelling the causes of this increased early mortality. In this review, changes in cardiovascular, nutritional and inflammatory parameters during the first year of HD, as well as changes in physical and functional performance are discussed. Treatment-related factors that might contribute to these changes include vascular access and pre-dialysis care, dialysate prescription and the insufficient correction of the internal environment by current dialysis techniques. Patient-related factors include the ongoing loss of residual renal function and the progression of comorbid disease. Identifying phenotypic changes and targeting risk patterns might improve outcome during the transition period. Given the scarcity of data on this subject, more research is needed.

Dialysis initiation: what's the rush?

The recent trend to early initiation of dialysis (at eGFR >10 ml/min/1.73 m(2) ) appears to have been based on conventional wisdoms that are not supported by evidence. Observational studies using administrative databases report worse comorbidity-adjusted dialysis survival with early dialysis initiation. Although some have concluded that the IDEAL randomized controlled trial of dialysis start provided evidence that patients become symptomatic with late dialysis start, there is no definitive support for this view. The potential harms of early start of dialysis, including the loss of residual renal function (RRF), have been well documented. The rate of RRF loss (renal function trajectory) is an important consideration for the timing of the dialysis initiation decision. Patients with low glomerular filtration rate (GFR) may have sufficient RRF to be maintained off dialysis for years. Delay of dialysis start until a working arterio-venous access is in place seems prudent in light of the lack of harm and possible benefit of late dialysis initiation. Prescribing frequent hemodialysis is not recommended when dialysis is initiated early. The benefits of early initiation of chronic dialysis after episodes of congestive heart failure or acute kidney injury require further study. There are no data to show that early start benefits diabetics or other patient groups. Preemptive start of dialysis in noncompliant patients may be necessary to avoid complications. The decision to initiate dialysis requires informed patient consent and a joint decision by the patient and dialysis provider. Possible talking points for obtaining informed consent are provided.