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

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.

Effect of Pretransplant Dialysis Method and Vintage on Early Clinical Outcomes of Kidney Transplantation

BACKGROUND

Pre-transplantation dialysis duration and modality may affect patients' long-term (mortality and graft failure) and short-term (delayed graft function) outcomes after kidney transplantation. We aimed to assess the impact of the method and duration of dialysis therapy on the graft function in the first 6 months post-transplant.

METHODS

The analysis included 122 kidney transplant patients (109 from a deceased donor and 13 from a living donor). Before transplantation, 91 were on hemodialysis (HD), 19 were on peritoneal dialysis (PD), and 9 received preemptive transplants. The incidence of delayed graft function (DGF) and creatinine levels at discharge and 6 months after transplantation were assessed.

RESULTS

PD and HD patients did not differ in age, number of mismatches, and cold ischemia time (CIT), but they had a significantly shorter dialysis vintage (18.3 ± 25.7 vs 39.6 ± 34.3 months, P = .01) and a lower incidence of DGF (5% vs 37%, P = .006). The duration of hospitalization and creatinine concentration at discharge and after 6 months were similar. Preemptively transplanted patients had a significantly shorter CIT (ND vs DO - 576 ± 362 vs 1113 ± 574, P = .01; ND vs HD - 576 ± 362 vs 1025 ± 585 minutes, P = .01). DGF did not occur in any of the patients transplanted preemptively. They had slightly shorter hospitalization times and, compared to HD, better graft function at discharge. After 6 months, creatinine levels were comparable to HD and PD. Patients dialyzed for less than 12 months, regardless of the method, had a lower incidence of DGF.

CONCLUSIONS

Peritoneal dialysis and a short duration of pre-transplant dialysis may improve the early results of kidney transplantation.

The Removal of Uremic Solutes by Peritoneal Dialysis

ABSTRACT

Peritoneal dialysis (PD) is now commonly prescribed to achieve target clearances for urea or creatinine. The International Society for Peritoneal Dialysis has proposed however that such targets should no longer be imposed. The Society's new guidelines suggest rather that the PD prescription should be adjusted to achieve well-being in individual patients. The relaxation of treatment targets could allow increased use of PD. Measurement of solute levels in patients receiving dialysis individualized to relieve uremic symptoms could also help us identify the solutes responsible for those symptoms and then devise new means to limit their accumulation. This possibility has prompted us to review the extent to which different uremic solutes are removed by PD.

A Review of Residual Kidney Function in Peritoneal Dialysis Patients

Residual kidney function (RKF) has been associated with better survival, less morbidity, and improved quality of life in peritoneal dialysis (PD) patients. Since higher peritoneal clearance does not lead to better outcomes, more emphasis should be put on preserving kidney function. Many other benefits have been reported, including better volume and blood pressure control, better nutritional status, lower rates of PD peritonitis, preserved erythropoietin and vitamin D production, middle molecule clearance, lower Left Ventricular Hypertrophy, and better serum phosphate level. The most practical method of assessing RKF is the mean of 24-h urinary urea and creatinine clearance. Incremental PD prescription is an ideal option to supplement RKF in PD patients, which also offers more flexibility to the patient and, possibly, improved adherence. Angiotensin converting enzyme inhibitors and angiotensin receptor blockers should be used when possible in PD patients to preserve RKF. Loop diuretics are underutilized in PD patients despite providing an additional means of maintaining fluid balance and reducing the need for higher glucose-containing PD solutions. In this paper, we outline the importance of RKF in PD patients and the different strategies for its preservation.

Epidemiology of peritoneal dialysis outcomes

Peritoneal dialysis (PD) is an important home-based treatment for kidney failure and accounts for 11% of all dialysis and 9% of all kidney replacement therapy globally. Although PD is available in 81% of countries, this provision ranges from 96% in high-income countries to 32% in low-income countries. Compared with haemodialysis, PD has numerous potential advantages, including a simpler technique, greater feasibility of use in remote communities, generally lower cost, lesser need for trained staff, fewer management challenges during natural disasters, possibly better survival in the first few years, greater ability to travel, fewer dietary restrictions, better preservation of residual kidney function, greater treatment satisfaction, better quality of life, better outcomes following subsequent kidney transplantation, delayed need for vascular access (especially in small children), reduced need for erythropoiesis-stimulating agents, and lower risk of blood-borne virus infections and of SARS-CoV-2 infection. PD outcomes have been improving over time but with great variability, driven by individual and system-level inequities and by centre effects; this variation is exacerbated by a lack of standardized outcome definitions. Potential strategies for outcome improvement include enhanced standardization, monitoring and reporting of PD outcomes, and the implementation of continuous quality improvement programmes and of PD-specific interventions, such as incremental PD, the use of biocompatible PD solutions and remote PD monitoring.

The use of peritoneal dialysis (PD) can be advantageous compared with haemodialysis treatment, although several barriers limit its broad implementation. This review examines the epidemiology of peritoneal dialysis (PD) outcomes, including clinical, patient-reported and surrogate PD outcomes.

Peritoneal dialysis (PD) has distinct advantages compared with haemodialysis, including the convenience of home treatment, improved quality of life, technical simplicity, lesser need for trained staff, greater cost-effectiveness in most countries, improved equity of access to dialysis in resource-limited settings, and improved survival, particularly in the first few years of initiating therapy.

Important barriers can hamper PD utilization in low-income settings, including the high costs of PD fluids (owing to the inability to manufacture them locally and the exorbitant costs of their import), limited workforce availability and a practice culture that limits optimal PD use, often leading to suboptimal outcomes.

PD outcomes are highly variable around the world owing in part to the use of variable outcome definitions, a heterogeneous practice culture, the lack of standardized monitoring and reporting of quality indicators, and kidney failure care gaps (including health care workforce shortages, inadequate health care financing, suboptimal governance and a lack of good health care information systems).

Key outcomes include not only clinical outcomes (typically defined as medical outcomes based on clinician assessment or diagnosis) — for example, PD-related infections, technique survival, mechanical complications, hospitalizations and PD-related mortality — but also patient-reported outcomes. These outcomes are directly reported by patients and focus on how they function or feel, typically in relation to quality of life or symptoms; patient-reported outcomes are used less frequently than clinical outcomes in day-to-day routine care.

The rationale for the need to study sodium-glucose co-transport 2 inhibitor usage in peritoneal dialysis patients

The wave of kidney and heart outcome trials, showing multiple potential benefits for sodium-glucose co-transport 2 (SGLT2) inhibitors, have excluded patients with an estimated glomerular filtration rate below 25 ml/min/1.73 m2. However, dialysis patients are at the highest risk of cardiovascular disease and would benefit most from effective cardioprotective therapies. There is emerging evidence from experimental studies and post hoc analyses of randomised clinical trials that SGLT2 inhibitors are well tolerated and may also be effective in preventing cardiovascular and mortality outcomes in patients with severe chronic kidney disease, including patients receiving dialysis. As such, extending the usage of SGLT2 inhibitors to dialysis patients could provide a major advancement in their care. Peritoneal dialysis (PD) patients have an additional unmet need for effective pharmacotherapy to preserve their residual kidney function (RKF), with its associated mortality benefits, and for treatment options that help reduce the risk of transfer to haemodialysis. Experimental data suggest that SGLT2 inhibitors, via various mechanisms, may preserve RKF and protect the peritoneal membrane. There is sound physiological rationale and an urgent clinical need to execute robust randomised control trials to study the use of SGLT2 inhibitors in PD patients to answer important questions of relevance to patients and healthcare systems.

Peritoneal Dialysis for Potential Kidney Transplant Recipients: Pride or Prejudice?

Kidney transplantation (KT) is recognized as the gold-standard of treatment for patients with end-stage renal disease. Additionally, it has been demonstrated that receiving a pre-emptive KT ensures the best recipient and graft survivals. However, due to an overwhelming discrepancy between the organs available and the patients on the transplant waiting list, the vast majority of transplant candidates require prolonged periods of dialysis before being transplanted. For many years, peritoneal dialysis (PD) and hemodialysis (HD) have been considered competitive renal replacement therapies (RRT). This dualistic vision has recently been questioned by evidence suggesting that an individualized and flexible approach may be more appropriate. In fact, tailored and cleverly planned changes between different RRT modalities, according to the patient’s needs and characteristics, are often needed in order to achieve the best results. While home HD is still under scrutiny in this particular setting, current data seems to favor the use of PD over in-center HD in patients awaiting a KT. In this specific population, the demonstrated advantages of PD are superior quality of life, longer preservation of residual renal function, lower incidence of delayed graft function, better recipient survival, and reduced cost.