Peritoneal Dialysis Update

This AudioScholar briefing is generated by artificial intelligence for healthcare professionals and trainees. It is not medical advice.

Welcome to your bi-weekly update in Peritoneal Dialysis. This period brings a double-blind randomized trial showing that a low-sodium dialysate removes more sodium. A change in laboratory culture technique cut culture-negative peritonitis by about a third. A cluster of observational studies looks at who leaves peritoneal dialysis for hemodialysis, from catheter technique to patient burnout to body weight. A systematic review finds that no peritonitis outcome model is ready for clinical use. A neonatal series reports very high mortality when peritoneal dialysis is used in critically ill newborns.

Sodium removal is where peritoneal dialysis most often falls short on volume control, and this period brings randomized evidence on a new solution. Nakayama and colleagues, writing in Kidney Medicine, tested a low-sodium solution at 126 millimoles per litre with 1.6 percent glucose [1]. It replaced one daily exchange and was used alongside standard bags. The comparator was a standard solution at 135 millimoles with 1.35 percent glucose. Patients at twenty Japanese centres were randomized two to one, and seventy-eight were analysed. Over eight weeks, daily peritoneal sodium removal rose by roughly 29 millimoles in the low-sodium group and fell slightly in the control group. Total sodium removal, water removal and dialysis adequacy showed no significant differences. The main drug-related adverse event was hyponatraemia, which was mild and fully reversible. The trial is small and short. Patients with preserved residual function on incremental regimens are overrepresented, and the test bag carried slightly more glucose than the comparator. The trial supports low-sodium dialysate as a way to raise peritoneal sodium removal. Whether that translates into better blood pressure, volume status or technique survival has not been tested.

Peritonitis remains the leading infectious threat to technique survival, and three papers address how it is diagnosed, what drives it, and what happens afterward. In Peritoneal Dialysis International, Nadarajah and colleagues report a single-centre quality improvement project covering 336 episodes [2]. Their laboratory added a water-lysis step and increased effluent sample volume. Culture-negative peritonitis fell from about a third of episodes to about a fifth, which means more patients could move to targeted antibiotics. 16S ribosomal RNA sequencing of culture-negative samples, done by Sanger sequencing, did not significantly improve pathogen detection. Only a few dozen samples were sequenced, though. This is a before-and-after comparison with two changes made at once, so the effects of lysis and of larger volume cannot be separated. The study supports culture methods along the lines of the International Society for Peritoneal Dialysis recommendations. It gives no evidence that this form of sequencing adds yield.

The second paper looks for a modifiable risk factor and does not find one. Bauer and colleagues, in Pediatric Nephrology, used prospective data from forty-six centres in the SCOPE collaborative [4]. Among nearly twelve hundred children, just over a third of patients had sustained hypokalaemia. Peritonitis rates were no different between children with and without hypokalaemia. Within the same child, months with hypokalaemia carried a peritonitis rate similar to months without it. This null result conflicts with adult cohorts that have linked hypokalaemia to peritonitis. The difference may reflect biology, confounding in the adult data, or this study's definition of sustained hypokalaemia. Adult cohorts using the same within-patient design, or a trial of potassium correction, would settle it. For children, this large observational dataset does not support low potassium as a peritonitis target, even though it is common.

Once peritonitis occurs, predicting its outcome is the next step. Wu and colleagues, in Frontiers in Medicine, applied the PROBAST tool to seven prediction models covering roughly thirty-eight hundred episodes [5]. No model reached an overall low risk of bias. Only one model had any independent external validation, and that validation was limited. None had a prospective impact assessment. The authors conclude that no model has enough evidence for routine use and that some may serve as research tools.

That critique carries over directly to the next set of papers, which ask who transfers from peritoneal dialysis to hemodialysis. Wan and colleagues, also in Frontiers in Medicine, built a model in seven hundred patients from several centres [7]. They treated death as a competing event, which is the correct approach because a standard Cox model overstates transfer risk when patients die first. A penalized Fine-Gray model performed best. Its discrimination was moderate, with a C-index of about two thirds. Its predictors were body mass index, previous hospitalization for peritonitis, and nutrition-related measures. The authors describe the resulting nomogram as having favourable clinical applicability. The PROBAST review reaches a different conclusion about models built this way. Wan's model was tested only on a random split of its own retrospective cohort, without external validation and without the calibration reporting the review required. The two papers address different outcomes, but they disagree on what counts as ready for clinical use. External validation with full calibration in an independent population would settle whether this nomogram holds up.

A different kind of predictor comes from Chen and colleagues in Peritoneal Dialysis International [8]. In a prospective single-centre cohort of 183 Taiwanese patients, about a quarter of patients reported emotional exhaustion and about a fifth had severe anxiety. High cynicism, a burnout component reflecting detachment, was linked to roughly three and a half times the risk of transfer to hemodialysis after adjustment for age and sex. The link with mortality did not reach statistical significance. The adjustment covered only age and sex, the sample is small and the estimates are imprecise. Cynicism may also be a marker of declining health rather than a cause of transfer. The study raises psychological burden as a candidate driver of technique failure. It is hypothesis-generating.

Body weight links back to Wan's predictors. Wang and colleagues, in Frontiers in Nutrition, followed 670 patients at one Chinese centre with body mass index measured at baseline, one year and three years [9]. They calculated how much time each patient spent within target ranges. Time spent between 26 and 30 was associated with lower all-cause mortality, while time between 24 and 26 was not. There were only seventy-five deaths. The study is single-centre and retrospective, and weight loss from illness may explain part of the association. The authors call their findings exploratory. Together with Wan's model, this work is consistent with nutritional status tracking outcomes in peritoneal dialysis. Neither study establishes a body mass index target.

Moving to how patients start dialysis: three papers cover catheter placement, the timing of initiation, and acute use in the sickest newborns. Rice and colleagues, in The American Surgeon, reviewed 429 laparoscopic catheter insertions at one tertiary centre [3]. Patients who received a prophylactic pexy stitch fixing the catheter to the anterior abdominal wall had about ten percentage points fewer one-year reoperations. That analysis excluded reoperations for infection or fibrin plugging. Omentopexy was nearly twice as common in the pexy group, the design is retrospective, and the exclusions shape the result. The authors describe their result as the first demonstration of benefit and also call for randomized trials. The second statement matches the design. The study supports the pexy stitch as a promising adjunct that has not been tested in a randomized trial.

Teoh and colleagues, in Renal Failure, studied 502 patients starting dialysis at a Singapore tertiary hospital [6]. Nearly three quarters of patients started unplanned. Those patients stayed a median of seventeen days at initiation, compared with four days for planned starts. Peritoneal dialysis was linked to shorter index stays in both planned and unplanned starts. After adjustment, unplanned initiation remained associated with more all-cause admissions over six months. The advantage of peritoneal dialysis was limited to the index stay. This is a single-centre retrospective study, and selection into peritoneal dialysis is likely to favour healthier patients. The findings add support for planned starts. They support urgent-start peritoneal dialysis as a way to shorten hospitalization but not as a way to reduce later admissions.

At the far end of acuity, Yıldırım and colleagues, also in Pediatric Nephrology, describe eighty-one neonates treated with peritoneal dialysis for acute kidney injury in one intensive care unit [10]. About three quarters of these neonates died, with a median survival of eight days after catheter insertion. Dialysate leak was the most common complication, affecting about one in seven infants. Acid-base and electrolyte values improved on dialysis. Hydrops fetalis was linked to roughly fifteen-fold higher mortality. Inborn metabolic disorders, fluid overload and perinatal asphyxia were also independent predictors. The study has no comparison group, and the deaths mainly reflect underlying disease. The authors present these features as tools for risk stratification and for counselling families.

If you read only one paper from this period, make it the low-sodium dialysate trial from Nakayama and colleagues in Kidney Medicine. It is the only randomized, blinded evidence this period. It shows that dialysate sodium concentration can increase peritoneal sodium removal. It also leaves open whether that removal improves volume control or technique survival.

The biggest change this period is randomized evidence that a low-sodium solution increases peritoneal sodium removal, though only in a short trial and without any gain in water removal. On peritonitis, laboratory culture technique has the clearest effect on culture-negative rates. Hypokalaemia does not appear to drive infection in children, which conflicts with adult data. No outcome prediction model has yet earned clinical use. Work on technique failure points to nutrition, prior peritonitis and patient burnout, all from observational and largely single-centre studies. The next things to look for are external validation of the transfer nomogram, randomized testing of the catheter pexy stitch, and outcome data from the low-sodium solution beyond eight weeks.

That's your Peritoneal Dialysis update for this period. Until next time.

This is an automated summary generated by artificial intelligence, which can make mistakes. Always review the original source materials.